omnipotentgoku

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1987 IROC Z
L98 350 TPI
AFPR
Holley hiFLO fuel pump
edelbrock intake manifold
Rebuilt block bored over .30


I am in serious need of help. My 87 IROC died on me saturday night. I was on the freeway doing about 70 on saturday night and I started to lose power. I got off the freeway and the car sputtered and the engine shook hard and then died.

I have since towed the car home, and can get the car to start (needed some gas as well) but it is puffing out plumes of dark black smoke at every revolution and its trying to idle at around 500 RPM (not stable at all) . I cant even rev past 3000 RPM...

- The car had been smoking previously on start up but was mainly white smoke. I believed the car may have had a torn AFPR diaphragm that was leaking fuel into the cylinders, but have not had the cash to fix it. That was white smoke, and it was not nearly as bad as this jet black stuff.

Any help brothers. I have no job, and have been desperately searching and this has become my daily driver since my sonata was wrecked months back. Thank you to anyone who can help.

Chevy8588

iTrader: (1)

jet black smoke = pig f*cking rich your FPR may be ripped wide open, pull the vacuum line off of the FPR and prime the system, see if fuel squirts out, if not then i would expect a stuck injector or 3. if the FPR is not leaking you need to remove your plenum and runners to lift your fuel rail and prim your system and check your injectors for leaking, other possiblility is a malfunctioning injector driver in your ECM keeping a bank constantly open. either way, your cylinders are getting burried in fuel, im leaning towards the ECM, but it may just be a bunch of leakers. (ohm your injectors before lifting the rail)

s10irocspikes

Unplug your mass air meter and see if she starts. Mine took a crap before and did the same thing. Good luck

omnipotentgoku

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seems like I should start where i was supposed to initially. I had thoughts that the diaphragm might be ripped. How do I ohm out the injectors, and what values should I see? I will do a search on the injectors but any help you can provide on that would be appreciated.

Toehead

Disconnect the wiring of of the injector and measure the resistance between the two pins you see. Should be about 16. Lower then about 12 and the injector is toast.

omnipotentgoku

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I am taking apart my plenum now. What do I do if it is a stuck injector or 3 ? Is their any way to 'unstick' the injectors or will they need to be replaced ? Also, I have primed the system with the vacuum hose from the AFPR off and it did not squirt. Since I will have the plenum off, I am going to check the diaphragm any way. I will also Ohm out the injectors while I have the plenum off. Any other suggestions ?

Chevy8588

iTrader: (1)

there is two ways for fuel to get into the engine.. injectors or FPR, if you are pouring that much smoke either a sensor is WAY off, or you have leaking injectors, only other thing i can think of is a stuck ECM driver for one of the injector banks

omnipotentgoku

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Ok...

I've ohm'd out my injectors and they all are at 14.9 (one at 15.0)

My AFPR diaphragm does not seem to be ripped.. I purchased a new one and will replace it.

I noticed that my plenum is black with soot..

I also tested the lines with one of those light kits and they all have pulse...

...

Justin89Formy

iTrader: (26)

test the injectors while they're hot if possible

omnipotentgoku

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How do you check them while hot ?

Chevy8588

iTrader: (1)

after running the engine to teperature, also, just a thought, check your throttle positioning sensor

Twin_Turbo

iTrader: (25)

Check the CTS, on another car (corvette) I've had a CTS go bad, making the car next to impossible to start and keep running and it was billowing out black smoke from running pig rich.

omnipotentgoku

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Ok, rebuilt the top-end , no change. Moving along to the spark plugs....

Something i've noticed, I am missing a header bolt. i had seen that one was loose recently but didn't act upon it. Anyone know what size the header bolts are on the L98 iron heads ? Also, could this be contributing to the problem ?

omnipotentgoku

iTrader: (1)

Where is the coolant temperature sensor on the car ?

Damon

Exhaust bolts are just common 3/8-16 thread bolts. Missing a bolt, even if it causes a slight exhaust leak, shouldn't cause the kind of catastrophic issue you're experiencing.

CTS is on the lower intake manifold, front, screwed into the coolant crossover near the thermostat housing, pointing approximately straight forward on a TPI, if memory serves. It's a 2-wire weatherpack connector going to it.

Agreed with above suggestions- all good ones. If you've got leaky injector(s) that's bad and it'll run pig-rich at idle (and won't affect the resistance reading across the injector terminals at all- a leaky injector would be a 'mechanical' issue with the unit). But try resetting the ECM and firing it up with the MAF unplugged first. If the MAF was the problem it'll throw a code but run much better right away.

If you can keep it running long enough, check the timing with the EST/timing wire disconnected (per factory timing procedures). 6* BTDC is the stock setting for most TPI engines. If it's "way off" without any change in the distributor's orientation you might have skipped a tooth on the timing chain, which will cause really bad running and lack of power "all of a sudden".

omnipotentgoku

iTrader: (1)

I was once told that the plug in the front of the lower manifold was not the CTS and that it was actually located on one of the heads... ?

As far as resetting the ECM, can I assume the best way to do that is to disconnect the battery ?

How can i find out if I have leaky injectors ?

This is getting out of hand, i've already seemingly wasted $55 on a diaphragm and plenum gaskets (that I don't have). I cannot afford to take it to a mecha to have it fixed....

camaro1185

If i remember correctly the there are 2 CTS's the one on the head (drivers side i think) only controls the temperature gauge. The one on the intake sends the info to the ECM.

Chevy8588

iTrader: (1)

yes, also, while you had the intake apart, did you pull up the fuell rail and check for leaking injectors? and did you check the voltage on your TPS if your TPS is stuck reading WOT and your throttle blades are closed, its gunna dump gas like hell

omnipotentgoku

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ok.... she's running... like crap.. but she's running.

Heres what I did.

1. disconnect the battery, and let it sit for a bit.

2. added more fuel (was extremely low when this started happening)

3. increased fuel pressure to 40 psi

4. Let it run for a few minutes , after which the black smoke is gone and I am now smoking, but its white smoke.

Basically I am back where I started. I had a problem with it smoking to begin with, that I should not have, but i've a running car for the moment.

She will now idle at around 7-800. I think ultimately my problem was that this car ran out of gas and everything else started to compound on it.

Here is a thought: I have a holley high flow fuel pump , plus 24lb injectors, plus an AFPR set to 40psi. Do you think that having extremely low fuel could effect the car in this manner with this combination ?


oh... and their was a plug on the distributor cap that was loose... that could have been it also.

omnipotentgoku

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Gahck!! I've not adjusted my TPS, gonna go do that now as soon as I find the instructions.. Just bought a new TPS a lil while back too. Didn't think of that.

omnipotentgoku

iTrader: (1)

help..... my car is embarrassing to drive now it because it spits so much black smoke. The car tries to idle at 600 rpm now (not good) and it stumbles massively. Im pulling and cleaning my plugs right now, they are jet black. Going to test my O2 sensor today, and try resetting my ECM again (disconnect battery for a bit). It seemed to play nicely last time I disconnected the battery. If it acts right again, then that would lead me to believe that its a sensor problem (or worse, the ECU) . I would much prefer that to a problem in the engine.

Also, what is the possibility that I am leaking coolant into the cylinders ?

Chevy8588

iTrader: (1)

coolant burning off makes thick white smoke that settles low to the ground. and oil smokes blue, fuel is what smokes black. there is too much fuel making it into your motor, maybe try unplugging the cold start injector? check your fuel presure at the rail on prime and see if it drops off hard, or holds stable.

Toehead

Check the coolant temperature sensor.

FSTFBDY

iTrader: (33)

This is not so.

That will put the ECM in a CLEAR FLOOD MODE:

When the ecm sees the engine being cranked, and the throttle angle is more than 80%, the ecm will shut off the injectors, or lean the mixture out to approximately 20:1 to help start the vehicle.


To the OP: is the check engine light on? It should be tossing a code if a sensor is bad. Then again Ive seen sensors go bad and not toss a code. (not common)

Deff. check the injectors ohm while they are hot. They would be more prone to coil failure while hot and stick open.

Another way to check if they are leaky is since you have a FP guage when you shut the car down does it hold fuel pressure for awhile or drop psi quick?

omnipotentgoku

iTrader: (1)

In saying "ohm them out while they are hot" should I run the car for the bit, shut it down and then pull the connectors and check resistance ?

I have since pulled all my sparks and did not find any oil on them. They were all Jet Black though and some had some white crud on them. (cleaned them with wire brush and reinstalled. I have also replaced my O2 sensor and disconnected the battery over night (clear ecm) . If this makes a difference (as it did before) but then goes back to its crap state, then it must be one of the sensors.

My CTS is new as I recently installed a dakota digital gauge cluster and it came with a replacement CTS. I've doubts about its location though as I have had conflicting reports of it being on the front of the lower manifold right under the throttle body(which is where I replaced it). I've been told that this may be the wrong location. Any truth to that ? (gauge works fine though)

Also, can anyone tell me where the knock sensor is and whether this might contribute to the problem?

- ohm while hot ?
- cts location ?
- knock sensor ?

FSTFBDY

iTrader: (33)

Yes run it for awhile. shut doen and Ohm injectors while hot.
CTS is in the front of the intake manifold. The one that cam ewiht your gueages should be the one in the head. for the cluster. the CTS is the signal for the ecm. 2 different sensors.

Knock sensor is on the P.side of the block above /forward of the starter.

Pocket

iTrader: (24)

Knock sensor is on the pass side of the block near the front of the starter. It has a single blue wire running to it and a round connector

CTS is in the front of the lower intake manifold. Look for two wires, yellow and black

There are three sensors related to cooling in your engine. Coolant gauge sensor in the drivers head between cyl 1 & 3 with a single rectangular connector and a dark green wire. CTS in the front of the lower intake manifold, yellow and black wires. Lastly, the fan switch in the pass head between cyl 6 & 8 with a single dark green wire and a connector identical to the knock sensor

The Knock sensor detects pinging or detonation or bad high frequency vibrations. In short, if the knock sensor reads too much whether its real or not it will put the ECM into limp mode and cause a good number of the issues you are having aside from the super rich issue. The CTS can cause the super rich startup if its bad and the test is simple, unplug it and restart. A leaky injector would cause it to run rich on one cyl, not all 8. AFPR should be easy to test, prime the system and let it sit. If you can watch the pressure bleed off the regulator is shot

Toehead

Or he has a bad injector.

I'm still leaning towards the CTS though. When mine went bad, the ECM was getting a constant temperature reading of 40 below, causing it to run super rich.

However, the ECM should set a code in this condition. Mine never did.

Chevy8588

iTrader: (1)

for some reason when the CTS goes bad on our cars, it will NOT set a code

Pocket

iTrader: (24)

Like I said a bad injector would cause one cyl to go super rich or super lean

If all 8 are the same then all 8 blew a seal (unlikely) or the problem is elsewhere

omnipotentgoku

iTrader: (1)

Okay... weird night...

As i am at my storage facility, my car craps out. Gauges say that I have 20% fuel left but I noticed previously that my car claimed the same or slightly lower when i first started having this problem. A friend brought me some gas and in the process a freak hail storm came and cracked my windshield... not gonna die over that.

Anyway.. I noticed that my fuel efficiency DROPPED massively. I was able to get less than 200 miles to the tank! I also ohm'd out my injectors as they were still hot and the all came out t 15.8 .

Im a bit lost here now not sure how to proceed. the only thin that i could imagine causing this problem would be the cold start injector. I will try to pull that and see what result I get.

Thanks for all of your help so far.

omnipotentgoku

iTrader: (1)

I saw in another thread that someone mentioned the possibility that the Catalytic converter might be clogged. If this is the case, how do I fix that and would that make any sense (regarding the massive fuel consumption) ?

I have cut outs that basically dump right before my Y pipe that I can open up, but seriously.. could this be it ?

FSTFBDY

iTrader: (33)

The cat converter wouldnt cause it to run rich. Runningway to rich will clog a cat eventually.

A clogged cat will make the car stumble and deff. feel a lack of power. I had a 355 in a elcamino ss and the cat got so clogged the car wouldnt start once it died.

You should really get a cable so you can do some data logging. Check your AFR , your BLMs and your knock count, etc..

omnipotentgoku

iTrader: (1)

On a side note, I have an autoxray 6000 (or 2000, forget which model) and I am unable to get it to communicate with the car. This is why I have not pulled codes yet. I have removed all of my emissions and heating/AC so I would always suspect that I would have some codes. The ALDL not responding to the scanner is another issue in its own but I just wanted to throw that out their.

transam85dudeman

ya dude, if youre losing that much fuel its got to be a stuck injector.. I say swap the injectors for some new ones, and take the old ones and get them serviced through the mail or something. Know more embarrassing looks, your car will run like a dream. youll be happy. its worth it. smile dude. at least hail did crack the hatch, knock on wood

Toehead

But if all 8 are running rich, it can't be a bad injector.


ohm out the cts. There is a chart on here with temperature versus ohms.

Toehead

http://www.kemparts.com/TechTalk/tt13.asp

Chevy8588

iTrader: (1)

for ***** and giggles drop your cat, a clogged cat WILL smoke, a clogged cat WILL bog your car down. drop it and fire it, see what happens, its only 2 bolts anywaysi cant see a coolant temperature sensor failing at temperature and suddenly reading a low temp, as for your scanner not talking with the ECM, check ALL of your fuses, also check all of your connectors, and as well as that, try jumping pins a and B on your ALDL and see if that works, if it does ad the MIL flashes then your scanner just doesnt have the right protocol for your ECM. also is your MAF functioning properly?

omnipotentgoku

iTrader: (1)

whoa... think I may have found it....

My Cold start injector.

If i remember correctly, when i sent off my prom to get reburned, I asked the dude to disable my cold start. (live in El Paso, a cold day here is like 50 degrees at very worst)

SIDE STORY: Last night their was a freak hail storm that came through on only one side of town, I was on the road then and got stuck in a flood that was high enough to creep into my passenger wells. This blew a few fuses and i've spent the greater portion of this morning pulling debris out from under the car ( no real damage, just a lot of twigs and such). Among the fuses blown was the fan fuse. My fan is set to run all the time, so before i checked the fuse, I checked the wiring as it was submerged and is not weather-packed. When I turned on the ignition, I heard this weird noise a few moments later under the hood that I had never heard before (because the fan was always running) I believe this was the cold start injector. Which leads me to this train of thought.
End side story


Now to my knowledge it had been disabled all this time. I just unplugged it (didn't even know it was actually still sitting their, thought we plugged it up) and ohm'd it out.... 4.5 !!!! I've read a lot of posts about injectors and that would seem to indicate that this injector is dead as hell.

I have since unplugged it, and the car is running... better. I now fully understand that a working TPS sensor will determine idle and kill the car as well so I am going to adjust it momentarily and take her out for a spin. She is still smoking a bit, but I don't believe it to be nearly as much as before. I will keep you updated. Thank you for everything thus far.

omnipotentgoku

iTrader: (1)

Ok... test run completed.. still running smokey.... but with a slight change in fuel pressure (turn the screw in) my idle evened out INSTANTLY and im no longer blowing black smoke. Stands to make sense that if I am running rich, decrease the fuel pressure, but what should I be running at.

This is my setup
MSD 6AL
Accell Coil
24lb ford injectors
holley AFPR
Holley hi-flo (forgot the rate, but one of the highest) fuel pump
350 bored .40
LPE cam

Various other stuff thats probably not pertinent to this conversation.

What fuel pressure should I be running with this setup ?

(I still need to do my timing because I believe it to be off, i need to find out why my ALDL doesnt respond, and adjust the IAC properly)

Chevy8588

iTrader: (1)

props to the guy that mentioned the cold start injector 20 posts and 3 days ago >.> anyways, good to see its running again

omnipotentgoku

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Hey im willing to admit where im wrong and post up everything i've tried so that it might help someone else. Would you agree that the cold start seems horked if its ohm'd out so low ? Also, anyone have any idea what an ideal fuel pressure would be for my ride ? Its running better but still hesitant on the throttle, it stumbles a lot.

Toehead

could be! Not necessarily though. The bad ohm reading only means the coil is shorted, not that it's leaking.

Glad you got it figured out though!

omnipotentgoku

iTrader: (1)

hmmm... still not running right just yet... I have the TPS set right now, just gotta find that good balance of fuel and air. I think I may be starving it now....

omnipotentgoku

iTrader: (1)

What do you have your fuel pressure set too ?

Chevy8588

iTrader: (1)

key on 40.5-47PSI
idle 30.5-44 PSI

set it so you get those numbers, a shorted coil on the cold start COULD have it stuck open. I'd get a cold start block off.

omnipotentgoku

iTrader: (1)

Where do i get that block off ?

I think the only problem ive really resolved is the smoking. It still stumbles like someone trying to clear their throat and doesnt have a steady idle. I need to learn to change my timing now. Is their an article that details how to do this for TG's ? I have a general idea but I am hesitant because the notch on my balancer is not visible from up top. its hidden under the marker tab . I dont know if that made any sense.

Toehead

You also could have fouled your plugs while running pig rich. Also, smell the oil to make sure it isnt saturated with gas

Chevy8588

iTrader: (1)

a trick for timing, the makr is the entire width of the balancer, take some white out and hit the notch with it, unplug the EST connector (near the blower motor sticking out of the harness) start your motor, connect your timing light to your no. 1 plug wire and look down behind your water pump while hitting that area with the timing light, then turn your dizzy accordingly. set it to 6* btdc. as for a block off, i think TPIS or SLP seels one, not sure, pull the injector out and see if it leaks.

+1 on the fouled plugs, take em out and use a map gas torch to burn the crap off of em.

irish887j

Your timing is def crucial to the performance of the Car...your gonna have to find a way to get that notch visible to a timing light (maybe draw a line across it as best you can with a straight edge and a whiteout pen...but it absolutely has to be inline with the notch)...from there disconnect the brown single wire above your heater box on the passenger side...once this is done have a buddy hold the timing light and the other one turn the distributor to I believe 6btdc...tighten the distributor, shut off the car, and then restart...the ecm will self adjust from there......

Now after that definately check out the article for setting your minimum idle followed by the one for adjusting your tps...doing these two things in order are crucial as well to getting the tpi functioning properly...