running into a few problems tho.

I have put an 85 top end on a 75 350 block. everything fits correct. i have put new venom 19 lb injectors on it, which the prom is set for. all new gaskets. no holes found in the diaphram on the regulator. return line unplugged 1/4 in size (5/16 is plugged at the tank). plenty of fuel delivered thru a msd pump. motor seems to be getting hot quick. if i unplug the #2 & #4 injectors it runs better and smoother. i can hear the computer making adjustments to the timing to try and smooth it out as well as the fuel adjustments to smooth the idle.

Timing is set to about 6.
IAC has been set to zero.
TPS at about .45

any help would be greatly appreciated.

 

350 tpi's usually have 22lb injectors, if the prom is tuned for 19 i guess that may not be the problem. my .02

 

yes i realize the diff in the injectors for diff ci, but this is for a lowrider and not building for all out. from point a to b is fine for this project. i also noticed the plenum and runners getting pretty hot as well in a short a mount of time. this is my first tpi set up so im very green with the computers and such. i guess i cant seem to figure out why it runs better with 2 cylinders unplugged on the same side. the rockers were set from the rebuilder and at this time i cant hear them to tell if they are set right, have to get the exhaust hooked up.

 

got a digital on the motor today.
all injectors are running 15 ohms.
tps set at .49-.50
injectors getting .8-.9 at idle
i also found the 9th injector to be bad so i need to get a plug for it, using a 727 uses all 8 for starting.
fuel pressure is 41 lbs when the pump is running and falls off immediately when it stops.
when the motor is running the rail is seeing 32 lbs or so constant. i read somewhere that when the regulator is getting vacuum its suppose to go all the way down to about 10 or so with 10 lbs of vacuum. and if the regulator isnt bringing it down that far would this mean that there is a vacuum leak somewhere? i dont have a vacuum gauge to check it.
im wondering if the 30 or so lbs is making the injectors stay open even without input from the computer.
i had an idea of unplugging the injectors and then pulling the spark plug wires and seeing what it does then.
i kind of did some experimenting and i can run the motor with all of the pass side injectors unplugged. and it doesnt run have bad either.
i can set a bypass up on the fuel lines to be regulated by a needle valve.
does the system have to have the 40 or so lbs to start or can i just set the system for like 10-12 lbs and run it that way?

 

Tps should be set at .54 or higher no lower than that>

 

The fuel pressure on a TPI should be *about where it is on your engine - depends on the year of the regulator.

mid 40's when vacuum reference to regulator is unplugged. Mid 30's when idling and reference line is connected to the regulator. Most pressure gauges are cheap and don't read correct pressure for squat, so don't get too fussed up about that. It won't run on 10-12 - that's for TBI.

The pressure is not supposed to drop off at key off. It's usually the regulator not sealing when key is off, but that won't cause your problems. Leaking injectors, and a bad/no checkvalve in the fuel pump are the only other two choices - aside from an obvious fuel line leak.

I think a 727 ECU doesn't care too much about the TPS setting, as it just learns the key-on value or lowest value it sees, provided it's within a certain range. The 727 is a corvette ECU, and the stock memcal should have a chip that is for 22 pph injectors. Change them (the injectors or the chip) or drive slowly and creap up to give the fuel block learning a chance to compensate. Never floor it - it won't learn when floored and the injectors are about 15% too small for the calibration in the chip. It will use the learn value from medium throttle driving, which will give it a better chance at getting enough fuel to keep it on the rich side, so be sure to do some driving with some medium throttle before considering flooring it.

The 727 also should control the fans differently than a 730. Might want to search the DIY PROM board for the differences. What wire harness are you using? If corvette, maybe not a problem.

It's truly amazing how well a V8 can run on 4 cylinders, isn't it. Power sucks, but the idle isn't completely terrible.

Running better with injectors disconnected sounds strange indeed. If the cold start injector is leaking or on always, and somehow is only getting to the passenger side from blocked passages or something, that could explain it. You should go ahead and see if there's a difference between injectors unplugged and spark plug wires unplugged. That'll tell you if that cylinder is getting fuel from somewhere else. Be careful though, and get the engine idling, then unplug the IAC, to keep the ECU from changing the idle speed. That'll give you more noticeable changes when disconnecting things.

Get's hot quick? Air pocket in the cooling system? Or definitely TPI related?? Do the fans turn on? Do you have a check engine light installed? Might be that the engine is in "limp home mode" if there's some problem. Limp home mode is quite rich.

Just tossing out a bunch of stuff here, hope some of it is useful,
Good Luck

 

it seems my regulator is working fine then because i have it set for 42-43 lbs not running and 31-32 with it running and vacuum hooked up. only thing is it wont hold the pressure with the pump off. the chevk in the pump is working as well as an additional i put in line.

according to the books that ive read .45-.55 on the tps is fine at its currently set at .49-.50.

the 727 i got when i bought averything didnt have the prom so i had one burned. set for 19 lb injectors (which are new but after checking the original they are ok too as far as ohm test), no vats, no emissions, for 350. i also used a new speed density wiring harness. i put in a 175 thermo switch for the fans seems to be working nicely now.

i know that the hard parts are in good shape with no blocked passages. like i said earlier the cold start injector has 0 ohms so i know its bad. its hooked up to the fuel by no wiring is hooked up to it. im trying to find a delete for it. it may be causing that pass side to be rich causing the 2 cylinders being unplugged to run better. i have noticed that the service engine soon light flashes the whole time ive had it running up to this point but may change if i can get that cold start out of there.

as far as the geting hot problem i think the fans have taken care of it when i put the new switch in for controlling just the fans. but what my concern is is that the plenum and runners are very very hot and they get that way in a very short amount of time. i guess my thinking is that with the cold air traveling thru it it would stay relatively cool.

 

The service engine soon light flashing means there's a problem with the ECU or prom burn. It is running in limp home and the only thing you can do is get the ECU/prom fixed. The custom burn probably has a problem like a checksum error, burned to the wrong location, cylinder select error, etc... Could be that the chip is inserted into the memcal incorrectly or incompletely.

The proper way for the SES light to show a working chip is a flash, a pause and a constant on. Flashing constantly is a big problem and shouldn't be driven that way, unless someone is trying to kill you or you are trying to kill the motor.

That coldstart injector has to go, especially if it's dead and spraying all the time.

Good luck

 

ran it today and had the 4 & 6 injectors unplugged and running good. took off the spark plug wires and no change but if i left the spark plug wires unplugged and plugged the injectors back in it takes a little while longer but the rpms go down and starts running rough again. i have also plugged the 9th injector so thats not a factor any more. i took it out and turned the fuel pump on it was not leaking i thought maybe the vacuum was pulling fuel thru it maybe not. no matter now.

i thought that if the ses flashes all the time it is running rich with the aldl jumpered. if its not jumpered it comes on for just a second after i start it and it is doing that. ill have to double check the light situation because my interior is ripped out including the dash. have to hook up my led last time i checked there was no codes.

 

Is it BLINKING on and off continuously? That's what I thought you meant. That means there is a chip error. This automatically puts the ECU in limp mode. There is no mechanical fix for this other than get the chip problem figured out.

If you mean always on while running, and not blinking, then it's just detecting a trouble code and may be running in limp mode, may not. A scantool would help troubleshoot that problem more easily, and i don't mean just read the codes, I mean look at the data to see what's going on.

In the previous post, I meant that the SES light should come on and stay on if you DON'T start the car. But a normal engine should show SES while cranking, and then go off once started.

You may also have some bad injectors somehow spraying more fuel than desired, but that would be strange. Have you double checked the firing order and spark plug wires to see that they're all in the correct places.

Does it run well at any time, like cold, or is it always crap?

 

blinks the whole time the engine is running and the aldl is jumpered, cold or warm.


"In the previous post, I meant that the SES light should come on and stay on if you DON'T start the car. But a normal engine should show SES while cranking, and then go off once started."

this is correct and mine does this.

i guess ill double check the ecu and see if the chip isnt in it all the way. and contact the guy that burned it to see what he can do. i can pick up a ecu for like 30 to check it too.

 

no no, I'm confusing you, sorry. Without a jumper, it acts "normal" right?

The blinking without a jumper is abnormal.

The blinking with a jumper is normal.

Flashing the codes with A-B.

Flashing closed loop status with some others. Fast blinking - open loop, slow blinking = closed loop. Or something like that.

If it's thinking things are normal, then things elsewhere are probably cuasing a problem, or the calibration in the chip is so messed up.

 

no jumper=light on engine not running light goes out after starting engine

jumper=flashes 12 when engine is not running and flashes when running warm or cold.

im at a total loss now for what to do next. i have had a guy suggest new plugs even tho these are new. i have less than an hour on the engine. never know. dont know what it would be if the plugs dont help.

 

Maybe a wire harness problem. Check to see that neither of the pins on the injector connectors are grounded (resistance to ground < 100000 ohms), with the ECU disconnected, and then with it connected.

If the wire harness has a problem like that, it could be turning those injectors on all the time, which could be causing your problem. Then check to see that the wires in the harness match the computer's pinout diagram (from a book or on the net).

 

we have checked the injector plugs with w niod light and they are pulsing. they may be pulsing too fast tho. i have checked all of the pin outs earlier and they seem to be all right. checking with the guy who burned the prom and asked for some trouble shooting suggestions as well. waiting to hear from him.

 

if the injector wiring got on the wrong side of the motor or was wired wrong could it cause this problem? will check this when i get home.

 

No, on TPI all injectors fire at once (165, 730, 727). They all fire once per revolution (i.e. twice for one intake stroke).
Some FYI - That's called batch fire. Even though there are two wires connected to the ECU, inside the ECU they connect to the same injector driver. The injections aren't synced to fire on any particular cylinder, just every fourth reference pulse from the distributor, which can be random at each start. Once started it stays synced to the same cylinder events, but the ECU has no idea which ones.

If the injectors are blinking with a noid, then it's probably safe to assume that the wiring is OK. I'd consider having the injectors checked out.

BUT, I'd first check compression on all cylinders, to rule out a problem with valve adjustment, etc...

 

The prom is basically an AUJP with VATS, EGR, and AIR disabled. The injector size is set to 19 lbs. I went back and looked at the .bin file I have on record for him, and everything looks fine. Checksum was calculated and saved.

unkuthz, I just sent you an email with a couple of things for you to try. I just though of a few more things....

I'd be curious to see what the plugs look like, particularly on the passenger side bank. See if you can pull them when you get a chance, and compare them with one another.

You know you have current going to the injectors, but you haven't confirmed that the injectors are all firing (unless I missed something in your post). With the engine running, place your fingers on the body of each injector (don't skip any, do this for all 8). You should feel it clicking very rapidly. If you come to one that isn't clicking, it isn't firing. If the connector for it checks out fine with the noid light, then that would make a bad injector. A bad injector would also cause the header primary for that cylinder to stay cold (assuming you have headers).

 

i pulled all of the plugs yesterday and they all have some carbon and not wet, uniform in appearance. this is not normally true i did wait a while before i pulled them yesterday. normally if i pull them right away 4 and 6 will be dry and the others wet. which would be true if they are getting fuel but no spark being batch fired, correct?

the last time i checked them all of the injectors were clicking, i could feel the vibration. but i will check again something may have changed.

something i have not received a response to is why the plenum and runners get so hot. i could understand some heat transfer but this **** will burn you within just a few minutes. if all it has is cold air being brought in then why so hot?

i also rechecked the compression and they are at 120-125 across the board. i also rechecked the rockers by tightening to where i couldnt turn the pushrods with my fingers and then another half a turn. i would think this would rule out a mechanical falure/problem somewhere. i also checked the plug wires and they are providing plenty of spark, that i can confirm. was bit quite a few times yesterday!!

i have also had the scan tool hooked up and there is no big fluxuations in timing so there is no reason to think it may be the distributor. altho i did notice yesterday that it seemed when i did have 4 & 6 hooked up they were firing thru the exhaust. hard to tell with open headers.

well thats about it for now.

wait, i think i hear a holley 650 carb calling me! thanks for the help. hope to get it figured out soon.

 

What's up with the EGR valve? Could it be stuck on, or not blocked off properly?

The valve adjustment, do you mean you took up the slack and then a half turn, or took them until it was literally very difficult to turn? The right way is until you feel drag on both ends (and can't shake the pushrod), and then the recommended number of turns. Otherwise you may be bottoming out the lifter plunger, and then opening the valve a half turn (I made that mistake when I was 15 - idle was a bit rough). The compression readings are quite low, but, no two gauges and engines are the same.

Could be tons of EGR heating up the manifold, or misadjusted valves shooting burnt gases back through the intake (less likely).

Keep at it, EFI is cool and will teach you a lot more about engines than justanother carb.

 

egr has a block off plate specifically for this year. has a notch on the bottom side so the gases can pass freely.

yes i may have tightened the rockers down too much. causing them to stay open.

i havent put a vacuum gauge on it yet, what should it be while idle?

 

Your egr plate lets the gases from one hole to the other? That would cause continous exhaust gas flow back into the intake. That would make for your rapid/high intake temp, and cause it to run really crappy....

 

so the block off plate will block off both holes not letting any gas go anywhere? i thought it was more of a little bypass type of thing, always letting a little go by. because there is a recessed area on the bottom side. unless of course im a dumba$$ and i put it on wrong and the completely flat side goes on the intake.

 

all that I was ever around had to be totally blocked off. even if you had a functioning egr, the computer shuts off flow at idle.

 

any news?

 

ill have some time to take a look at it tonight. can i bench test the injectors? thought i might get a resistor and give it like 1 volt and see if it clicks to make sure it works before i put it all back together.

 

I believe you can put power to one post and tap ground to the other. -

 

Yeah, you can power one side and tap ground to the other, just tap the ground well away from injector and fuel, becuase it will spark (done it several times). Without fuel pressure it should only click. If you have a spare injector connector, it would go more quickly.

AFAIK, the EGR block off is supposed to be a block off, not a bleed. Flip the cover and try again, can't hurt, and is likely the cause of the burning manifold temps, and possibly the missfire if some of the internal passages are plugged up and biasing everything towards those few cylinders.

Good luck.

 

i worked on the monte yesterday and turned the egr block off plate over so there was no bleed by. runs like a champ now. i also had a couple of injectors stuck, gave them a little tap and they are working fine so far. thanks for all of the help and suggestions.

exactly how far away from the head do i have to put a 1 wire o2 sensor? i have a set of chrome headers and right now it is in the collector. and i was told that was too far away. i might have enough room to put it on the backside of one of the tubes. just wanting to find out how far is too far away from the head for it to work right.

thanks again for all your help.

 

Congrats!
A one wire can work "OK" down there, but I'd recommend switching to a 3 wire heated sensor (just get 12v (up to 4 amps on it so get a tap into a good circuit) to one of the white wires and ground the other white wire). Popular opinion is the AC-Delco brand (not the Bosch).

If the sensor cools off, the ECU will know and won't usually cause any real problems, but won't stay in closed loop. If you drive it in a cold winter, some have seen the sensor cool off then, but usually OK in warmer climates.

The distance also affects the idle a little due to the extra distance and the response time of the exhaust reaching the sensor. This can cause a slight rpm oscillation.

DON'T put it in one tube or pair of tubes though. Either leave it as is, or get a heated sensor.

 

i think that its working fine because the flash is a lot slower now than it ever was. open is a fast flash and closed is a slower flash right? or the other way around?