-srs-

Like the title says, the car starts and runs OK for 30 mins or so then gets rougher and rougher. It sounds like it's missing, then dies and won't stay running after I fire it again. I can hear the fuel pump pressuring up when I turn the key though I haven't tested pressure. The engine throws no codes. Plugs and wires are about a year old. I'm going to follow the diagnostic at the following link.

http://easyautodiagnostics.com/gm_ic...n_module_1.php

What else should I be looking for? It's beautiful down here this time of year...just a really rotten time to have a broken convertible!

vetteoz

iTrader: (13)

Do the ICM diagnostic hot ,
not uncommon for them to work fine cold but have problems when they heat up.

Also check the heat sink compound under the ICM , if that fails, the heat from the ICM can't be transferred away and it can overheat

-srs-

You're right. Just stepped out to the garage and it fired right up. It's idling as I type this. Guess I'll close the hood and wait for it to die.

I wouldn't be surprised if it's the icm.

86 toy

iTrader: (1)

ohm your injectors hot they should be above 14 ohms, also take your dizzy cap off and have a look at the pickup coil under the rotor.. i just had a very similar problem with my 92 TPI 305 and i had 1 bad injector and a very rusty/ corroded pickup in my distributor. replaced injectors with Bosh III's, pickup coil and ICM. Problem fixed!

-srs-

I have a moates USB data logger but I can't get it to work. CPU blinks 12 so I know it's OK.

-srs-

Ignition system checks out. Moved on to fuel. I put a gauge on the schrader valve on the fuel rail but I get zero pressure. The pump runs for 2 sec. Car starts. Gauge doesn't move. WTF? It's just a screw on adapter. How can I be screwing this up or how can the car be running with a zero reading at the rail. If I step on it, the car dies.

-srs-

I should get a good squirt of fuel when I press the schrader valve right? I replaced the filer 500 miles ago. I want to blow out the lines but I've never done it before. Does the fuel reail have to come off? I guess that'd be a good time to ohm the injectors.

Jersey89GTA

iTrader: (1)

Ohm out the injectors, takes 5 minutes, I just found 3 of the 8 were bad. Mine runs great cold then shakes like a **** when low idle drops in.

Bosch IIIs are on the way and a new Fuel reg.

Yes to replace injectors rail has to come off.

Go on youtube, theres a guy who uses a pressure can thing hooked to rail Schrader and injects FI cleaner right into the rail with pressure. He pulls fuse on fuel pump and runs car off of FI cleaner for like 5 minutes.

On YT, search "fuel injectors"

-srs-

Thanks. I'm watching your thread to see how it turns out. Our problems sound very similar. I thought the injectors needed to be out of the car to ohm them?

Jersey89GTA

iTrader: (1)

Nope, you have to unplug them obviously to get to the pins, then they are isolated.

Some say the should be warm/hot for better reading.

BlackJet

Jersey,
Got a question, because I've developed a similar problem and have been searching for the answer. You said:
Ohm out the injectors, takes 5 minutes, I just found 3 of the 8 were bad. Mine runs great cold then shakes like a **** when low idle drops in.
Mine runs pretty decent when its cold (5.7 TPI) BUT RUNS WORSE THE WARMER IT GETS? Feels like a very prominent miss, and it's driving me crazy.
Before I tear everything from the manifold up off and start over, does this sound like the issue you described?

Jersey89GTA

iTrader: (1)

Theres a few cheap and easy things you can do before you tear the top off.
86 toy mentions the same things and symptoms I had

1. OHM out the injectors - pull caps put a meter on it, its real easy ........ here's a vid on YT on a TPI engine

2. Check TPS - set to .54v

3. Check dizzy - I had two bolts were broken inside and the thing was flopping around.

4. Plugs/ wires/ distrib - tune up.

5. CTS ? they are about $15-20

But Ohming the injectors is free and doesn't req any tear down until you need to replace. See what you got.

86 toy

iTrader: (1)

My car had a prominent miss once it warmed up also and it was 1 bad injector on number 2 cylinder... warm your car up good and get an ohm reading on all 8 injectors.. just unplug them and check them with a digital volt meter set to ohms.. they should be above 14 ohms I think.. 1 of mine was at 5 and the rest at 16.7 but I replaced all mine with the bosh III ones from south bay.. my car runs like a champ now.. no misfires and good power.. best $160 I spent on the car!

BlackJet

Very, very helpful information, and great video. Much thanks to the both of you for that. I have repeatedly heard that Southbay is the place to go for injectors, so I will most likely be a near future customer. I will be doing those checks tonight.
I love this car, and love it better when it's running the way it should.

Jersey89GTA

iTrader: (1)

Yep let us know.

You never know what cb wrong, but these are the easy and first things you can try or check without breaking the bank. One of mine was .004, so that's got to be my issue.

South Bay is a sponsor here, and they are very helpful from what I read.
I did buy mine off ebay for $120 set of 8 - rem-man'd, tested and balanced, guaranteed for 3 yrs. Didn't know about SB till afterwards, in hind sight I would have supported the club sponsor.

BlackJet

Jersey,
TPS reset to .52, was .74 but I had reset that before and it fixed idle issue.
Last night injectors were 17.0 across the board, with two at 16.8 on right bank.[B] However,they were NOT hot when I checked them, so am doing that today, and that doesnt mean they are clean, right?
You mentioned CTS, what is that?
Anyway, moving through you guys checklist one item at a time.
Mark

BlackJet

17.6 across the board, two 17.4s hot.

Jersey89GTA

iTrader: (1)

OK, looks like your injectors are good - try Seafoam, about the best FI cleaner there is, Lucas is good too, dump it in tank.

CTS is coolant temp sensor, located just above the water pump and below the coolant line that feeds the throttle body. I changed mine out w/new. Just have new one ready w/ Teflon tape on it. Back the old one out and swap in new one real fast so minimum coolant runs out, couple drops. (Eng cool)

its a long shot, but CTS can throw havoc threw the computer if its getting wrong readings and cause weird fuel ranges or even put car into limp mode.
If you say you're affected when it gets hot, maybe the CTS is telling computer that your too hot or still cold ?

Check the plug in first, make sure its good, not corroded.

Like I said it's a long shot - crap shoot, but again, cheap and easy.
02 sensor an do weird things also, but mostly runs car rich.

BlackJet

Jersey,
Hows the weather up there my friend? Its 72 here.
Thanks for staying with me on this.
Followed this: http://easyautodiagnostics.com/gm_ic...n_module_1.php,
All good there, and you are right on the CTS, leads are corroded, and it is a heat issue.
Hotter it gets, it "flutters down the road". Shifts into it's "torque band" 1500 to 2500 rpm and just "flutters", no low grit. And boy does that **** me off.
Down here, folks like there BMW's and traffic seems to be a competitive event. Well, like a true "northerner" I dont like to loose.
Was always scared of seafoam, do not know anything of it.
Injectors do not seem to be leaking, even after 25 years, but I'm thinking I should just replace them anyway.
CTS is outta here, and school me on the EGR valve, sensor, and the fuel pressure sensor if you will.
Mark

Jersey89GTA

iTrader: (1)

Put any fuel inj cleaner in if your not sure, give it 2 doses at once see if it helps.

Egr is simple, but have to take plenum off. Buy a AC delco only, no cheapo NAPA ... problems w/them. If you have the plenum off clean it up real good inside. Remove the IAT and the IAC. Since you are having temp related issues, replace the IAT under the plenum w/new, looks just like the CTS.

EGR will cause rough running - but your SES light should activate code 32
- either Valve or Solenoid, usually the valve. Go on youtube and search
"EGR Test" ... vids show how to check if valve is bad.

-srs-

Removed the fuel rail yesterday. When I was disconnecting the return line, I got a lot of leakage...I mean a LOT. There was more pressure on the return line than on the supply by far. The car has not been cranked in a week. Cracked the gas cap, the pressure released and the leakage stopped. That can't be normal can it?

Jersey89GTA

iTrader: (1)

Yep, tank is pressurized, every time I open it - sounds like air pressure relief.
Both cars do it -TA and Camaro. Seems that car runs better with the cap tight and tank pressurized.

I took my fuel rail off on Sunday. I opened fuel cap, removed fuse by the battery while car was running and it instantly died.(90's have FP fuse there) I pushed shrader valve on rail and very little pressure left. Came off pretty easy. But the bracket that holds fuel lines - that bolt is in a bad place, what a bitchMaybe an angled wrench ?

Took off belt and tstat housing so I could get a better swing on the wrench.
Needed to reseat the tstat gasket anyway - leaking.

I also did a new fuel reg, while I had the rail off, figured why not ?

I got an Oring set w/ the FReg, the fuel lines at the 2 compression fitting have Orings, should those be replaced too ?

BlackJet

Jersey,
Thats funny you should bring up the pressure in the fuel tank issue, and I'm glad you did.
I've been doing alot of reading here, and wondered about that myself.
Mine does not now, but I distinctly remember it did before, and I wondered if that could be a contributor to runability issues that so many on here talk about or around.
Alot of talk reference vented and non vented gas cap, broken or dry rotted lines to and from the gas tank ect.
I try to read before I post, to avoid looking dumb, but same as others, in search of a sollutuion to a problem.
I am going to pull all from the intake up off and reseal that, so I only have to do this once.
I found an article that Im sure has been posted here before, but, along with you and some of the other guys advice, seems to help make sense.
I will post it here shortly

BlackJet

http://www.corvettefever.com/techart...HlCsObSU.email

Jersey89GTA

iTrader: (1)

I'm a happy camper ... got the car all back together today, runs very smooth.

Had to pull the rail off again, one injector was leaking, turns out I pinched an oring in the rail seat. Replaced Oring -Oiled the $hit out of the o rings and popped back on easier ....

Fired it up - feels nice and smooth at idle.

-srs-

The guy at Southbay said to seat the injectors in the intake first and then put the rail on. Seems like it would be harder that way but what do I know...it's my first time doing this job.

Jersey89GTA

iTrader: (1)

I followed that method too(put in intake) both times, not a problem, since there are no clips in the Bosch 3s, really the only way. If they were multechs w/clips you'd have to put into rail first.

Now I just noticed the Schrader valve leaking a little ?? Wonder if I need a new valve or maybe tighten up the stem, I tried my tire Schrader tool, but it wont fit.... have to investigate. Caps for these things ?

Jersey89GTA

iTrader: (1)

Found this in the search, maybe helpful to someone ....

Saved it to my library.

-srs-

Mine has a cap but it's really only there to keep debris out of the valve. I'm not sure if you can replace the core on those or if you just have to replace the whole thing.

-srs-

Didn't make much progress this weekend but I did check for blockage on the return line, charcoal canister and the valve leading to the canister. Couple of questions while I'm waiting to my plenum gaskets to arrive.

First, how do I test the solenoid on the canister? Is it 12v or less? I don't want to cook it trying to test it.

Second, is there a way to test the egr valve? As long as I'm in here, I might as we'll replace it but I don't want to if I do t have to. That $70 can be useful elsewhere.

Jersey89GTA

iTrader: (1)

Picked up some AC system cores ... and caps(pak was $7). Caps have Orings inside them,

Going to try the new core out if it don't stop leaking.
_______________________________________________________
Edit: Well that was an easy fix, the kit I bought had a matching schrader core and a cap.

Put the new one in and no more leaks.

Took it out for a ride tonight - feels like a new car, No more gizzly bear under the hood, smooth as a Cadillac....... I know to some of you guys this seems kinda blah and insignificant, but this is monumental for me.(Injector job and Fuel Reg)
Learning as I go.

THE CAR RUNS FRIGGIN GREAT !! and I did it myself, was always scared of messing with fuel systems, was always afraid of a disaster. Usually when I fix plumb it leaks even , more. LOL

Thanks to everyone that gave advice and contributed !! Much appreciated.

Johngypsy

Hi guys haven't red the entire form, but I have a hopefully solution here-

I have had the same issue with not one,, but 2 cars all or both with Tpi cars doing the same issues, when started after 10!sec try, it would feel as if the cars had a sickness and would stall out, hesitate, die out, mis fire, and even idle like it has a fever and shivers....

Can't or couldent find a solution after several weeks, from days to weeks, and moths, and did every single thing to the cars, which could of installed a ls1 with all the parts done, literally everything listed in the book and on this site, it was all done!

Finally, after a day I had on my day off, I bought a set if used injectors at friends house, even though all the injectors were at 16.5 across the board, installed them any ways as ok, I'll just try it, well guys it fired right up with no issues, went and got another set for the other 89 Iroc z car, that's was also the same, 16.7 across the board, installed all 8 with all new O rings, and again, fired right up, no issues what so ever,

Turns out, the resister in some injectors of a standard brand, will show fauls oms signals, the older types, (gray) so for all you guys out there waning to sell your baby and pride and joy, or wanting to go with a carb? Wait!!

Just invest into a nice brand of injectors if I was you, also take out your A.I.R and spray it with carb cleaner really really good,,, while your right there,

If 1 injector is off by .5 to .9 in any one of the 8 injectors? Your car will do all what the guys here are going threw, this is what you would atleast expect, theses tpi cars are very hard to take care of, what I mean is: don't run alwas regular into your motor, General Motors knew this, but they never told us to do so, because it was supposed to be a sports car that's on a mild budget, BUT! If you owned the same 89 corvette? With the same l98, gm had told and placed a aticker on the instrument cluster to use premium fuel, so do you know what I mean? Use super or at least 89 octain with sea foam or some sort of fuel additive to keep these injectors clean, at least once every few weeks, the reason why we all love these motors? Is because not the horse power, but the look, (if cleaned and looks factory) as it would look so much prettier then any ls1 or any LS motor out there, that's why we love them so much!

Well I hope that you guys with this issue will try and don't give up! Just invest another few hundred dollars into it, and would say go with a 24 pound injectors instead of the factory 19 pounds, eBay has them for about the same price, and it's worth it, with a fuel pressure regulator ( adjustable )

Reply back guys and tell us all how it went if you go with a set of new or flow matched ones,

Good luck guys!
John