Chevy86 IROC-Z

iTrader: (17)

Im not bashing on you. I actually like the clean mod. Most access mods are pretty dirty. Yours is quite clean. Like I said, I prefer to do the job right. No dissing intended.

TTOP350

iTrader: (8)

Some people without the proper tools misdiagnose and guess at their cars problem..

Having a lil extra air psi in the tank is waaaay better than having a some vacuum. The psi makes the pumps work easier.

I have a fuel psi guage also.

moldman

Just had the same problem Saturday on the way back from a show. I have had the noise from the vent valve in the past but it never shut the car down before. This time I could restart the car but I could watch the fuel pressure sit at 41 psi then start to drop when the vent valve would start to whine. The fuel pump is only a couple of years old and the pressure regulator is a year old. Now it was a 100 degrees Saturday and I was on the highway for about an hour when I came into town when the car fell flat and then stalled. And at this point I had a little under a half tank of gas. The common thing with eveyone is the hot weather. I did most of the checks that the service manual says to do and everything has passed. The next check will be the volume that pump is putting out. When I find out more I will post it up.

Chevy86 IROC-Z

iTrader: (17)

This just in. My Bro-n-laws 87 IROC has the same humming/whine sound too. Get this, My bro has no muffler under his tank. So with the sound of escaping fumes (pressurized), then there is only one other source of heat, the fuel return. My bro has a HSR system. So hopefully this sheds some light that the muffler is not a source of the issue at hand.

gch

I have been having these same issues. Saw some other threads and changed the ignition module today. Now the vacuum fluctuates but it did not die on on hot start. Fuel pressure was right on at 10 psi and engine temp was at 220 deg F. All sensors have been changed within last two years and fuel filter & pump in 3.5 years old.

I haven't changed the fuel tank vent valve yet but its next on my list.

gch

Oh mine is an RS with TBI, so much lower fuel pressure tha the TPI.

moldman

How many of use have the water bypassed on our throttle body? I know the idea is not to put heat into the TB but the top half of that intake is exstremely hot. The gas moving through the rails is acting like a cooling system for the intake. Just saying.

Chevy86 IROC-Z

iTrader: (17)

I seriously disagree. The fuel rail ONLY has 12 points of contact to the intake manifold (4 bolts and 8 injectors). That does absolutely nothing in relation to cooling anything. The conductive and radiated heat from the block and cylinder heads is the source of the whole majority of transferred heat. A percentage of the heat also comes from the radiator. So as for the fuel rails having a cooling effect is not relevant to the situation nor does it cool anything. I don't think it would even classify as a heat sink.

Chevy86 IROC-Z

iTrader: (17)

This may further complicate the issue of heated fuel causing the humm/whine. I knew I was running low on fuel when I moved my Camaro. I reversed hard and I heard the whine. Keep in mind that I had barely turned on my camaro in the morning and there was no time for my fuel rail to heat up. So any fuel that was returned to the tank was more than likely the same temp as when it was sucked up by the pump. If any thing, the fuel may of had risen by a few degrees as the fuel passess close to the exhaust headers. So in my case, the noise was present just after start up and the temp outside was approximately 95 degrees.

moldman

My comment was in regard to the fact that the fuel temp was recorded around 128 degrees when fuel pressure was lost and the vent valve started to whine. I was on the highway when the motor started to lay flat and when I came into town she had enough. I was only on the road for about an hour and the temp outside was around 98 degrees. My coolant temp is only 160 when I'm on the open road and my fans will come on at 180 when I am in town. But you could cook under the hood and you would not be leaving your hand on my intake very long. An hour is a lot of time for heat to soak into the intake and my tank was down to just a little over a quarter tank. My headers do not get that close to my fuel lines plus the ceramic coating on the headers should keep the heat to a minimum. All I know so far from reading everyone's post is the temp is over 95 degrees outside, fuel temp is high and the pressure in the fuel cell is high. I just want answers like everyone else on this thread.

panhead201

Cooler fuel is more explosive,air gap intakes,my superchargerhas cooling lines tee,d off the heater core lines,directly from the water pump and returning to the radiotor.Ever sit at the drag strip and watch your fuel lines ice up waiting for the light to turn green?Alcohol and nitrous.The reason for nitrous heater blankets,so your lines don't freeze up,especially if you purge it,just before you hit it.panhead201

panhead201

So the whining sound you heard was your cap venting.Well,thats good news.caps are cheaperthan fuel pumps.Is your cold air intake hooked up and clear?I had a mouse build a nest in a cold air intake on an 84 crossfire vette so I cleaned out as much as I could and took off the rubber gasket? that connected the air cleaner to the intake tube.That made it worse.The temp under the hood was unbeIievable.It was running closeto300.And by then all the coolant had boiled off and I was getting water out of ditches by the side of the road.Thats the one thing I really don't like about this T/A.no grille.I'm gonna buy one of those body kit front ends.Its got about a three foot wide mesh grille in it.anhead201

panhead201

https://picasaweb.google.com/1109234...78036331221474

panhead201

11

Chevy86 IROC-Z

iTrader: (17)

Looks good. I like the Super Charger.

panhead201

$400 bucks on craigslist.It'd never been out of the box.Whipple wants 8 grand for em.Now I gotta make sure the rest of the driveline can handle the horsepower.I've been reading the SCCA rules and I think I can slide it by.When I pull this sound system out I'll send you some pics and you can tell me what you think.Sounds like It's your thing.All I know is guitar amps,tube type.This guy has gold like 10 guage wire connecting everything.The car dont look bad.Thats not why I got it but it dont hurt.I traded him a bass boat fror the car,anew stroker motor with $1500 heads on it and a kawasaki motorcycle.He wanted the boat pretty bad,I guess.
This stroker has a 68 vette 327-375horse block and a nascar shop did the machine shop work.It's the best I've ever seen and I've been doing this a long time. the heads and the tpi came with it.I tried to download a picture of it.Don't know if it happened or not.panhead201

panhead201

yeah,it worked and the kawasaki,s behind it.I made the headers for the 305 in the car now.panhead201

panhead201

he reason I posted the picture of the tpi is I think they did it like that is so cooler air would surround the plenum.panhead201

panhead201

I've been bitting here wondering if anybody had tried that,nowI know.THANKS,panhead201.I had my car too far apart to try that.

GOATS2QUICK

iTrader: (5)

more fuel for thought, today as i was filling up, i could feel the gas handle warming up as i filled the car. hmmmmmmm?

Chevy86 IROC-Z

iTrader: (17)

How does a gas pump nozzle handle heat up if your hand is insulating it by wrapping around it? If anything, your hand is heating up from the fuel vapors. So if the handle is heating up, its not from the hot vapors escaping the tank, its the fuel that is traveling through the handle. So the gas that is stored underground must be hotter than the atmospheric air.

Fuel for thought.

T/Atime

lol, i dont know about that bud!

panhead201

It seems more likely that the air you're displacing with gas coming out of the tank is warming up the handle.Fuel stoored in underground tanks,if thats where they're at,is almost always gonna be colder than feul that just took a ride through your fuel system.It's been over a hundred degrees here every day for three weeks and every time you stop and put fuel in anything around here your met with escaping hot vapor.Even plastic gas cans I've left in the sun have expanded till they're out of shape.You can park your car in the sun here and go out and put your hand on the car anywhere and its gonna be hotter than the outside air temp.So it has to be the backpressure in the tank,not the fuel temp,thats causing problems with the fuel pumps.And you are'nt gonna stop and get fuel if you've got three quarters of a tank,And fifteen gallons of air is gonna have a lot more pressure in it than a few gallons of air,especially when its being filled with fuel that just took a ride through your engine thats raising the temp of the returning fuel,no matter how hot.I'm gonna drive around with the gas cap loose on something,where its screwed in there but not enough to build up pressure.The fuel pressure on the inlet side has got to be causing problems,not the actual fuel temp.panhead201

Chevy86 IROC-Z

iTrader: (17)

No Comment. Post #170 is not relevant to the topic.

panhead201

[quote=Chevy86 IROC-Z;5035499]No Comment. Post #170 is not relevant to th I don't know man.I just can't give up on a problem without at least thinking about it,and it seems like too many people been having the same problem for there to be something doing it.You'd think a pressurised tank would put out more fuel,not less.Do you think the noise is innadequate venting through the cap?If ,lets say for the sake of argument,hats the case,it could be affecting the back-flowflow preventer in the pickup tube,or pump,wherever it is? Anyway,I'm gonna go out and pull that stereo equip. out of rhe car today and I thought I'd send you some pics if I can figure out how to do it,or at least some names and models and you could tell me if its any good or the kinda stuff I oughta mount upside down in whatever I put it in. Nice bird in your pics man,I was a UH-1D driver from 70 to 75.My oldest boy is a lifer,Master crew chief on a B-1 in Abilene.Except he just got promoted last week to accident investigations.panhead201He'll be here tuesday.Have'nt seen him in 2 years.First he spent about a year on some little rock in the Indian ocean called Diego Garcia.

John Galt

its been a while since i weighed in, life caught up with me and I had to put my iroc problems aside for a while. While the loud whine of the fuel pump is the easiest indicator of when the problem is going to stop your car, it appears as i read through the pages of posts since my last visit that the thread has turned into a discussion about how normal it is to whine, and why it whines, and how much whine is acceptable, and what brands whine the most. I think we're slipping into a different topic altogether. While the whine seems relevant to the problem, I don't care if the pump sings yankee doodle dandy to me, it is the car dying on the side of the road that's really getting me down. I'm wondering if some of the people posting aren't even having the car shutting off problem. Not bitching at all, I haven't even been around lately. It's just a reminder to anyone coming late to the thread who maybe isn't reading every post to get to the end of what the thread is all about.

And for anyone wondering I haven't gotten around to doing the FPR move I discussed a while back, but I'm still doing it; just a funds availability problem at the moment. You'd think that having 4 cars would leave me pretty set for transportation, but recently I've found that it really means you can have 4 cars break at once. Bad luck I guess.

I also realize this thread may die soon as Oct. is approaching and many having this problem will also have it disappear till spring unless they live in FL like me or somewhere else ungodly hot.

Also, I think I'll break down and jump into the whining discussion my self. I know the pump whines. I hear it for a few seconds when I turn the key on. That's not the whine I'm dealing with. I end up eventually with a whine that I can hear over a flowmaster muffler, with the windows down, and the radio on, progressively getting louder and louder until the car dies as if out of fuel. Also I can hear it from the outside of the car. If I'm not in the boondocks when this noise starts I pull over at the nearest gas station and top off the tank. I don't turn off the car when I stop for gas, usually I have my wife in the car and leave the air conditioning on. If the tank is down around a quarter, it is uncanny fast how quick the whine quiets down so much you can't hear it anymore. 2 seconds maybe as the new "cool" fuel is dumped into the tank. Above a half a tank it takes 10 seconds or more and is more gradual, but the same effect. After adding new fuel I get about another 30 - 45 minutes before it happens again, and hopefully I'm home by then. Bottom line, I know pumps whine, this is not a normal whine, and fuel temperature in tank is totally controlling the whine, and controlling the whine controls the eventual failure that follows.

panhead201

I have been thinking about and sometimes I start out complicated and work my way back.It sems to me that the fuel pump impeller,the spindle it rides on,for lack of a better term,is lubricated by fuel.The lower the fuel,the higher the temperature it would seem.Returned fuel from the engine is added to less and less fuel every moment the engine is running.I was wondering if the increasing fuel temp in the tank is increasing the friction on the pump shaft,leading to failure eventually.Thats the best I've come up with so far.It'd be fun to install an aftermarket oil or tranny cooler to the return line somehow.It's definitely do-able,but you would have no way of knowing if a pump was destined to fail,therefore no way of determining if you had suceeded.I'll figure it out one of these day's,or not.panhead201

John Galt

Someone tried using a tranny cooler as a fuel cooler for the return line, it slowed it down but didn't stop it. The failure still eventually happened. It is a factor of the fuel temp in tank(for me at least), but the question is either why(too much heat being transfered to the fuel in the engine compartment/fuel rail before the FPR sends the excess back)? or how to change it. I'm planning to install an aftermarket fuel pressure regulator back near the fuel filter, so the excess returns to the tank without going through the engine compartment, fuel rail, etc...the fuel that returns to the tank will have only travelled about 3 feet before it turns around and goes back. I believe it will work but this car is number 4 in the list of my vehicles which need attention, so at least a month before I can try it, and if it works I'll never be sure if it is fixed or if it is because it will be October then, it is still hot in Oct here but not the same as summer, or even September for that matter. Its hot enough this month to have a failure but it wont be for very much longer.

Also I'm on third fuel pump with this problem, not all the same brand either.

T/Atime

im trying to understand what your attempting to do, your goal is to relocate the fpr. this in my mind will only pressurize the pump and line then dump 100% of the fuel right back to the tank. so the point is to just have the pump running to eliminate the possibility of the engine eg. headers, heads, temps messing with the fuel? like a "bench test"

T/Atime

how are these cars running before they heat up? has anyone put in on a a/f device to measure the cars are getting enough fuel at higher rpm eg. 4500rmps?

when i was going throgh all this a few months ago i relocated some fuel lines a few inches, wraped headers, insulated return lines and supply. these things did not help. my car would still die. i wish the trans. cooler was the answer, its been done before.

theres definitely more then one topic regarding these fuel issues.

Chevy86 IROC-Z

iTrader: (17)

I went to a car club meeting not to long ago. My temp gauge rose to 230*. I drove a total of about 30 miles non stop with FP whine. The temp outside was around 108* with 60% humidity. My Camaro didnt stall on me at all. I was more worried of over heating.

John Galt

T/Atime: im trying to understand what your attempting to do, your goal is to relocate the fpr. this in my mind will only pressurize the pump and line then dump 100% of the fuel right back to the tank. so the point is to just have the pump running to eliminate the possibility of the engine eg. headers, heads, temps messing with the fuel? like a "bench test"

The fuel pressure regulator lets the proper pressure level fuel (43 pounds or so) pass to the fuel rail and sends the excess (whatever must be bleed off to bring it down to 43 pounds)back to the tank. Now the factory one does it after it passes through the fuel rail on the passenger side and sends the rest through the return. Aftermarket adjustable pressure ones can be bought that are mounted on the side of the engine compartment which make the bypass before the fuel rail and send the excess back through the return line, much like the factory one does just in a different location. What location is ok? the driver side of the engine compartment? or would the passenger side be fine too? the working of it does not change no matter where it is mounted. What I suggest is mounting it under the car, back by the fuel tank, of course after the filter but that is right next to the tank. Cut it into the fuel line going up the the engine compartment. Cut into the return going back to the tank right there and send the excess pressure back into the tank, just like it does wherever else you would mount it. Regardless of where in the fuel line I mount it the FPR lets a certain amount of fuel at a certain pressure pass and sends the excess back to the tank. Why not mount it in a place that never allows the fuel to get heated in the first place. All the fuel that passes through to the engine will get heated as it passes through the the engine compartment and the fuel rail, but who cares, it's never coming back to the tank. The excess fuel required to be bled off by the FPR(same amount no matter where I mount it) will be returned to the tank, only difference will be this time instead of going all the way to the engine compartment(absorbing heat), through the fuel rail(absorbing more heat), then back through the return line which is welded to the fuel rail(again absorbing more heat) to be a constant stream of heated gas pouring into my gas tank; in this location the returned fuel to the tank will have only travelled about 3 feet to the FPR and 3 feet back to the tank. I'm not reinventing the fuel system here, I'm just moving a component around. It's kind of like if I was mounting it in the engine compartment; "could I mount it there?" ---Sure, "Could I move it over a foot?"--why not, works the same, "could I move it over 3 feet?"--of course. Well I'm proposing moving it about 12 feet, don't know why the rules of physics would change that much by adding a little more distance, it will be hooked up and functioning in the exact same way regardless of where I put it, but I can greatly control the tank fuel temperature by moving it. There has been the subject of how to get a vacuum line to it but I think the situation solves itself, because wherever I install it I will be abandoning the rest of the old return line which I could easily convert to a vacuum line. Its metal and goes all the way back to the engine compartment where I need to be to get a vacuum source. I think this will work. Only problem I foresee is that possibly there could be a delay when I went from idle to wide open throttle suddenly, would the FPR adjust quickly enough to the increased demand from that much of a distance? I work with pressurized fluids in my normal line of work and based on theory alone I would say yes. If not, I may adjust up the FPR a few pounds and see if that helps; but theoretically I don't see this being a problem anyway. I know less about vacuum so if anyone knows more and think the added distance would adversely affect the vacuum lines chime in. Right now I look at this as being the most promising solution, at least to my problems as mine relate solely to in-tank temperatures.

panhead201

I've had the fuel pump fail twice.Once in a crossfire and the second in an 86TPI.I was'nt paying attention to the fuel level the first time,but I was the second.I thought I ran out of fuel.Both times it was extremely hot outside.I don;t think I associated the two til now.I've gotta put a pressure regulator on my return line this week.I have to have at least betweed 12 to 13 lbs on my return or I have to install an inline pump and pressure regulator to my throttle body.I was gonna take the hard lines off my valve covers and run it behind the engine. if I do that,and there's no more exhaust back there now.So that oughta cure my problem,The new airtex pumps or whztever they are,seem like junk.panhed201

panhead201

You would think the engineers who designed it would have thought to put it in the best possible spot but they probably just found a place to make it fit.The in tank pump in my wifes 98 tahoe just went out twice this summer,So did my neighbors suburban(once)I wonder if it's got to do with ethanol or new gas blends?panhead201

John Galt

I would like to think its got to do with ethanol, it is sure causing a similar problem in the boating community and its got to do with lower vaporization temps, the only problem is that there are a lot of these cars out there and you would think they would all have the same problem if it were that easy. I found a place about 15 miles outside of town where you can buy non ethanol gas, and thought I would get a tankful and go on a long drive to test the theory; but when I saw the price of $5.25 a gallon for the 87 octane, I said the hell with it, I'd like to drive this car daily and I can't at that price. I think the ethanol is a factor, but I've still got to find a permanent solution, cause ethanol isn't leaving us any time soon.

John Galt

On another note, I think we all (the TPI owners) are on the verge of having this problem, only maybe many don't know it. I think the ethanol is making everything run hotter and mixed with the lower vaporization temp it is causing havoc in the pump impeller at a certain temp. When this happens to me I only need to let it sit about 2 or 3 minutes to get it to start again, although I will only get about 2 or 3 minutes of driving before it happens again. It's like if the gas temp drops 1 degree it will work, and when it raises 1 degree again it stops again. Like there's a real borderline that you cant cross. Many people here are running some small modification that must be affecting it in some way, or be just enough to push it over the edge. Like my self I have a larger exhaust than stock, maybe it's making a difference. Changed the ignition to MSD, wouldn't think that would do anything at all. Found out I'm supposed to have a heat shield under the tank, never knew that, someone before me must have removed it during the exhaust change. I still have to junkyard around and find one of those. And a lot of these owners don't live in an area where 95+ outdoor temp is absolutely common for months on end like I do. Even the owners who have never had the problem may be just a few degrees away from it. Maybe the heat shield would lower the temp on mine 2% and I would never have a problem again. It takes about 30 - 40 minutes of driving to heat it up enough to stall. It used to happen in 15 - 20 but one day I saw a bent bracket and noticed the return gas line was lying on the head. That small movement doubled my drivetime. I think it is just so many factors and such small degrees of improvement or worsening with each action taken its like trying to find the ghost in the machine. I'm still going to try the FPR move though, hopefully that will finish this problem for me. This has been going on for 6 months here where I live in Orlando.

panhead201

I've adding been a half a can of Sea-Foam per 32 gallons in my boat and it has quit that die for no reason then immediately start and run perfectly stuff it had been doing.panhead201

Chevy86 IROC-Z

iTrader: (17)

Okay. I recorded my FP whine/hum with my wifes camera. So when I downloaded it to my laptop, I heavily filtered all the low frequencies and high frequencies (Adobe Audition) to get the FP noise. Here is my case. I did stop and go, stop and go. Also in the description in the youtube video, I have time stamps that when you click on it, the time cursor will automatically jump to a section where you will hear my FP whine. The tank is at half ways and I only drove about 30 seconds from a "cold start" which is not enough time to heat up the fuel in the fuel tank. http://www.youtube.com/watch?v=c2r6I48m2DA

panhead201

My audio is not working at the moment.I just had to recycle my modem and re-establish internet connection with servers tech help.have wan now,no broadband.Severe electrical storm just went through,had to reset voltage protectors.You'll have to describe sound.Rising and falling,constant,whats up?Bill panhead201

Chevy86 IROC-Z

iTrader: (17)

So you have Wide Area Network internet connection but no broadband? Broadband works with coaxial cables such as those that use a coaxial cable for a multi connection device such as a cable box and modem. The modem has nothing to do with the soundcard either. But anyhow, I cant explain. You would have to hear it to know what Im experiencing.

panhead201

I have both,it's a long story,it involves my modem and router getting fried not too long ago and temp.connection til it could all get straightened out.I just had to re-log into about 5 minutes ago.So many paasswords,so little time.We can persue all this later if you care.It froze again since I sent you last message.Simple restart cured it.Back to the car,inbetween lightning bursts.What kind of noise was it making?Oscillating,steady,what?Bill

Chevy86 IROC-Z

iTrader: (17)

I get the whining when I apply the brakes or when I accelerate. Its wierd and hard to explain. But it seems like the swooshing of the fuel may be a cause. But its always when Im half a tank or lower. Could it be that it occurs when the low fuel gets over heated? Possible. But if thats the case, then why does the whine occure even after I turn on my IROC? So in my situation, the whine is not heat related.

panhead201

From what you are saying,the problem would have to be voltage related,it would seem to me.Draw of brakelights,etc.Most of these guys seem unaware there is a primer circuit that will whine when you first place ignition in run position.eg;My car whines for ten seconds.Thats irrelevant.Do you have a way of measuring current draw from fuel pump when you engage other high draw acessories?A/C comp,brake lights,turn signals,you get the idea.Would that lead to a cooked diode in fuel pump relay,other system that should isolate fuel pump circuit?A dead short in the entire 12.7 system.I'm just throwing out Ideas here,you seeem to have a better grasp of this part of it than I do.What do you think?............As far as my computer goes this one has wan and connections,it's routed to an IBM with XPpro,amilitary version thats not bootlegged,but I had hoped to isolate from online and did'nt.It's,and so's this 64 bit systems,theIBM is connected to a Fostex recording platform with production program capabilities,5.1 klipsch active monitor system 4 boosted inputs,mikes,drums,acoustics,you know the drill.I think the sound card in this one is cooked but I dont know that.I can't get it off mute and dont have the time or inclination to deal with it now.It's about 4AM central.The 5.1 sound is working perfectly on thee IBM is working perfectly,But not through this Toshiba high def monitor.It's all connected through rca,tv co-ax,1/8 inch st cable and fiber optic.Somethings rotten somewhere and I don't feel like fixing it tonite.I tried to download page on control panel that displayed the wan and lan connections to you but it looked like I was about to send you the entire hard drive,so I did'nt.If you feel like helping out sometime that would be great,but I want to get my car back together.












i think I'm gonna end up with an external fuel pump,Holley or Walbro,Have'nt decided yet.I'm gonna put a fuel cell in the boot,would love to keep em both,put a decent filler in the top,draw from the bottom.Gotta check the rules.Anyway,this has gone on forever.I hope you come to realize I've got no possible reason to bs you,and as far as you dissing me,I,m a big kid.I think I can handle whatever comes my way.And I don't bs so I dont gotta remember what I said panhead201

ZZ3Astro

I'm glad I found this post (not really, because now I realize this is going to be a very difficult problem to resolve).

I can confirm several things related to this problem. First, a quick history on my car. It (was) a competely stock 87 5.7 tpi with a single turbo. I cannot confirm exactly when I first noticed this problem (before or after turbocharging it). Fuel system is stock except for: Walbro 255 in-tank pump, charcoal cannister removed, 65 lb/hr injectors and I have been running the gas cap loose due to seemingly insane pressure build up.

1> For the problem to occur on my car, the engine coolant temp has to exceed 195 degrees.

2> The problem definitely occurs with both E10 and non-ethanol fuel - this was an early thought as I hate E10 and wanted that to be the reason!

3> It appears to affect volume more than pressure. I say that because idle and cruise are lightly affected while boost/WOT lean out beyond 15:1. I maxed out 65 lb injectors to 100% duty cycle and still went 16:1 at 10 psi!

When does it happen to me? Well with the stock engine, it only happened under extreme conditions that resulted in "high" coolant temps of 195-220 degrees. I say "high" because for a stock TPI it's completely normal to see 210-238 degrees, but for me I like to see it under 190 degrees. But certainly 210 is perfectly acceptable to the original fuel system design so... I dunno. Anyway, extreme driving conditions being a hot summer day, AC on and doing some boosting.. Or going to the dragstrip and hotlapping several times. Sure fire way to see 210 deg coolant temp. Like a Timex, as soon as I'd make that third pass in a row my AFR would reliably go to crap. HOWEVER, with the new engine all I have to do is drive the car around for 5 mins and my coolant is at 195+. Hence the reason I looked for and found this post - since this puts me into this problem EVERY TIME I DRIVE IT NOW.

Like others in this post, I have found my fuel temps to be in the 115+ degree range. Fuel rails 150+. A while back, I tried to diagnose this with a fuel pressure test gauge (borrowed) but the fitting leaked so I couldn't test it. During my new engine build, I ordered a new fuel pressure module for my digital gauge so as soon as I can get that on I'll be able to watch what is going on.

This situation has rendered my car useless for boosting and I have WAY too much time and money tied up in this new engine build not to be able to use it. Very frustrating.

RBob

iTrader: (1)

The CCP vapor control valve has a much lower cracking pressure then the tank 'mushroom' vent valve. Which is what is causing the high pressure in the tank.

The tank vent valve is easy to open and modify. Just need to cut the larger spring and re-bend the end coil flat and reassemble.

The other purpose of the tank vent is to allow air into the tank. The cracking pressure for this is already low so no need to change that function.

Getting to 195* F in 5 minutes seems to be too fast. It may be due to it being a new engine that isn't as free to turn (rotating friction) as an engine that has been run awhile.

Although my first thought was that the spark timing is off. Worth a double check.

RBob.

ZZ3Astro

RBob, thanks for the info. That's what I found.. the vapor valve just randomly vented while the car was sitting hot, resulting in strong gasoline odor in the engine bay. When I plugged that line (would love to keep the CCP but I'm running a Megasquirt and no easy way to configure purge), then the tank pressure builds up too much - hence the loose cap. I'll do that mod you posted to the tank vent valve though and will be in good shape.

I can't figure out this coolant temp problem. I actually started having it with the original engine and it is the main reason I built the new engine (totally different 350 block with 20k miles, std bore). The only major difference in the new engine configuration is I now have aluminum heads. My only guess is that the aluminum heads are pulling more of the combustion heat out and putting it into the water. I had LS1 (aftermarket) fans and went back to the stock duals with much better results. Then I replace the radiator (stock replacement) with almost no improvement. I've ran various thermostats, straight water, no thermostat, fans on early, fans on late, you name it. I added an external trans cooler and even added a third fan. I moved the intercooler outward to allow air dam pressure to go straight up into the radiator which helped a good bit, but still the car will stay in the 200 range. It won't cool down even while idling.

Timing is something some others recommended changing to ARAP bin numbers (going to the aluminum l98 heads from the irons) and I did make major increases across the board. This helped performance a good bit but had no effect on operating temps. Another thing is as far as friction goes, I did a bearing replacement with .000/.000 bearings and no maching on the journals. I put .000 rings in and the block was honed .001" so if anything, this engine has less friction than a typical new build.

Chevy86 IROC-Z

iTrader: (17)

Highly dought it. I have no A/C equiptment, no sounds system bumping ( proof is evident in the sound provided on youtbe video link that I poseted). Fuel Pump Relay (1 of 3 by the brake booster) is less than 2 years old. I sometimes dont turn on the IROC for 2 weeks (ruling out short in the electrical system) without weak current during cranking.The battery and altenator are less than 6 months old. Sound was present before and after charging system swap.

panhead201

I.ve solved my temp issues on rverything Ive built in the last several years.I use restrictors,the onr's Iuse are made by Moroso.They replace the thermostat and come in 4 different sizes in a pack.They are nothing but washers that have a specific size orifice in them.They dont allow the coolant to get too hot,thereby opening the thermostat,and I had a disasterous issue with a fail safe thermostat.Instead of sticking open when it failed,it stuck closed.These washers allow the coolant to constantly pass through the system.I lnow for a fact that you cant run without a thermostat.The coolant does'nt spend enough time in the radiator to benefit from the cooling principle.These washers come in 4 different sizes,resulting in 4 different average temps due to the flow rate and can't fail.I won't use anything else,You experiment with them and find out which works best for you,If you decide to try em,they cost about seven bucks for 4 and I think Ive seen em in autozone but any speed shop would definitely have them.I know from experience that aluminum heads transfer more heat into the engine compt. as do headers.I wont use headers that are'nt wrapped in a closed compt.You're plug wires live longer,too.panhead201

Chevy86 IROC-Z

iTrader: (17)

So you had a fail safe thermostat actually fail! So much for the extra cost of a anti-fail device.

panhead201

Yeah,a radiator hose ruptured and I was way out in the country.It was Sunday and it turned into an all day deal.After I replaced the hose I could only drive a few miles before it began to overheat again. when I got home I threw the thermostat in a pot of water and it was stuck closed,not open.Thats what led to the restrictor purchase.A conversation at my speed shop.panhead201