LT1 Intermittently Stalling

[FlyingDutchman]

Supposed to be heading home from school for the summer next Sunday and of course that's when car issues surface :facepalm:

Brief car history. 1997 Camaro Z28, 6-Speed, only mods are CAI, catback, and !CAGS. Purchased in 2008 with 64k, rebuilt shortly after due to a failed head gasket/bent rod. Currently has 95k on the clock, no major recent issues. All gauges read normal levels with nothing noticeably wrong.

So it rained earlier today when I left for my gf's house (2 miles away). Car ran fine like normal. Parked it and spent a few hours at her house so the car should technically have fully cooled off. Going to leave, I start the car and allow it to idle while I choose some bomb ϟƘƦןƖƖΣx tunes and I feel the car start to shutter and proceed to die. Starts right back up and idles for a minute so I decide to drive away. Car ran fine for about a mile, but then as I am coasting with my foot in the clutch down into dip I put it in 5th and release the clutch to accelerate up the hill. I notice that the car died again. Coast up the hill and creep along the shoulder and start the car back up. Make it back to campus where it dies at a stop sign. Starts one the third attempt and I make it to the apartments where a friend and I take a look at it. Allowed it to just idle and it idles smoothly and randomly chokes and dies. Did it a few more times, sometimes it would start right up, sometimes Id have to take a few attempts. Eventually I drive it across the street into the parking lot. Stopped the car and it died. Took some effort but died again and again. Finally I got it into my parking space where it currently rests.

From what I have read, there are only 303974139470916509 possibilities :bertstare:

The Service Engine Soon light was already on for rear 02 sensor, but no check engine light. SES light does NOT flash or anything indicating misfire. Have not been able to check out codes yet, hopefully will get a scanner asap.

When it dies I am not touching the gas or anything else to provoke it. Sometimes the RPMs will just kinda slowly fall to 0. Other times the engine will attempt to catch its self and rise to 1800ish rpm and either idle or die. If I hit the gas I can raise the RPMs easily and it seems fine.

In the past I have had the car do this before. Once I remember idling out of the driveway backwards and it died. Another time I started it while parked out front of the house and the RPMs dipped a few times before it caught itself.

When I was home removing the cutout, I noticed oil alllllll over from the back of the engine to the tail shaft of the tranny. Not sure if that has anything to do with my problem, thinking the RMS is leaking judging by where the oil was.


So LT1 gurus ... what should I be looking for? I have seen something about the coil being spaced off the head using a washer ... what's the point? Hopefully this is not a sign of a failing opti .....

I will attempt the gather more information and update you. Sorry for the long read, trying to include all that I know.


Thanks,

- Josh 8-)

[Blackbirdws6]

ICM could be giving you problems. Space it off the head with some washers. How is your fuel pump?

[greenformula92]

since you are descirbing the problem getting worse the warmer the engine is I am going to say ICM too.

btw the oil could be either a rear main or the rear seal of the intake manifold

[FlyingDutchman]

Tried starting it again this morning, first attempt it started rather weakly but didn't hold idle at all. Tried three times after that and only got it to turn over but no catch. I asked the fuel pump how it was doing and it said "wheeeeeeee" so I think that means its alive but I'll need to check the pressure to verify.

From what I read the icm becomes a problem because of heat soak.. Does that mean it will only act up when warm?

[LTb1ow]

Sounds like a dead opti.

[FlyingDutchman]

Sounds like a dead opti.

Wouldn't I experience misfires or something? I am uploading three video clips to hopefully provide a better idea of what is happening.

[LTb1ow]

When my opti went, it just died on me, no code or SES warning at all.

It threw the codes only the day after I had let it sit and then tried to restart it.

But like all things, check for all things before shot gunning parts. Spark plug wires not arcing, spark plugs good, good fuel pressure and good battery voltage. Since its not doing it at only hot temps I would say your ICM is prob not the culprit.

How old is the opti? Did you verify both vent lines are attached to it?

[FlyingDutchman]

I would assume that the opti has never been touched and is still the stock one. I will try and crawl underneath and look to make sure the vented lines are still connected (I don't think they would just fall off). Here's the video:

http://www.youtube.com/watch?v=F4ta0pfYowQ&feature=youtu.be

Hopefully its not the Opti.. that's a big job when I am 400 miles away and I have no trusted mechanics out here.

[LTb1ow]

Sorry to say thats pretty much what mine was doing when the opti decided to die on me.

I would scan it and see if you have code 16 or 36.

Code 16 opti low res will have you dead in the water unless its intermittent, then you will only be dead in the water when the code is active. 16 disables the fuel injectors, fuel pump, and the ignition module. Code 36 the high res code will allow your car to run, but starting may be difficult and performance poor when it starts. 36 lights the ses wile 16 does not light the ses.

You could also check the opti harness, see if just messing with it changes anything, they can go bad or have corrosion on the terminals.

[FlyingDutchman]

Sorry to say thats pretty much what mine was doing when the opti decided to die on me.

I would scan it and see if you have code 16 or 36.

Code 16 opti low res will have you dead in the water unless its intermittent, then you will only be dead in the water when the code is active. 16 disables the fuel injectors, fuel pump, and the ignition module. Code 36 the high res code will allow your car to run, but starting may be difficult and performance poor when it starts. 36 lights the ses wile 16 does not light the ses.

You could also check the opti harness, see if just messing with it changes anything, they can go bad or have corrosion on the terminals.

Well if it turns out to be the Opti like you are saying (I have a friend with a scanning program on his laptop, so I will get as much information as I can) what exactly is involved parts wise? Price range seems to be all over ... Is this as daunting of a task as everyone makes it out to be?

[WildBillyT]

Well if it turns out to be the Opti like you are saying (I have a friend with a scanning program on his laptop, so I will get as much information as I can) what exactly is involved parts wise? Price range seems to be all over ... Is this as daunting of a task as everyone makes it out to be?

Not daunting. Just take your time. And quadruple check your firing order.

[FlyingDutchman]

Is this all you need (aside from gaskets and sealants)? Found it on ebay:

http://www.ebay.com/itm/New-Optispark-Distributor-for-LT1-LT4-Chevy-GM-1995-1996-1997-/360426814176?pt=Motors_Car_Truck_Parts_Accessories&hash=item53eb1cbae0&vxp=mtr#ht_2368wt_1163

199$ Free shipping, 1 year warranty. Is it really worth the extra $250 for an MSD setup if I am only using this as a daily beater?

[LTb1ow]

I would be wary of cheap optis.

As far as swapping em, you just need to yank the water pump and crank dampener. Whether the dampener separates from the crank hub is questionable, so it may be easy to yank it all as one piece.

[FlyingDutchman]

Yeah last thing I want is to replace the thing twice...

So what would you recommend?

From Summit racing ..

ACDELCO
http://www.summitracing.com/parts/ACF-1104032/

Summit Racing
http://www.summitracing.com/parts/SUM-850060/

ACCEL
http://www.summitracing.com/parts/ACC-59125/

And there were a few other ones listed. What's the difference or what am I looking for? Are any of the ones I listed ok?

[LTb1ow]

AC delco or MSD.

[FlyingDutchman]

I take it there are two different MSD setups .. one for 150$ made of Rynite (Plastic?) and the 450$ made of billet aluminum.

Optis should be a friggen group purchase.

[LTb1ow]

I take it there are two different MSD setups .. one for 150$ made of Rynite (Plastic?) and the 450$ made of billet aluminum.

Optis should be a friggen group purchase.

AFAIK there is only one full MSD opti and then there is an MSD cap/rotor kit.

I have a MSD opti for sale if you want to get a used unit.

[FlyingDutchman]

I see you have both an MSD and ACDelco ... what's wrong with them?

[LTb1ow]

Nada, just going with the 24x setup so doing away with the optispark part.

[FlyingDutchman]

Ok I may take you up on that pending what I find after scanning it. Will code 16 only show up when cranking over? Or will it be stored in the memory?

[LTb1ow]

Mine was stored, I just ran the datamaster and it came up with the codes. No cranking.

[greenformula92]

Opti is not bad. When I did one in a 95 I had to take the fans out to get a gun down there to loosen the dampner bolts and then to have enough a room for the puller. that was the most difficult part of the whole thing. Water pump came right off, fans came right out and three bolts for the opti and boom its out. line the opti up bolt her down to like 10 in. lbs and put her all back together

[FlyingDutchman]

Update:

Last night I used some cheap engine scanner tool and the only code I could get was P0161 which is the rear O2 sensor. The scanner didn't provide any other information so I can't saying anything more about that. However, that code has been coming and going for the past year or so (if it makes a difference, I notice it usually trips under decent acceleration when the car is still cold). That was the only code that came up, so I removed it (probably shouldn't have). :facepalm:

Today I had a friend with a computer using autoenginuity software and didn't find any other trouble codes. The program was quite massive so I probably looked over valuable information ... oops. :bertstare:

After the scan I tried starting it again, it started and made it to about 2000rpm and immediately dropped. Tried again and got nothing. Third time killed the battery, not enough juice to turn it over (maybe like 1 revolution).

Since there were no codes related to the Opti I kinda ruled that out. Any easy way to check for spark? Like maybe a volt meter? Then I can say for sure there is spark.

Then I proceeded to check for fuel. I didn't hear any whine from the pump but that doesn't say much. I located the pressure valve on top of the intake and removed the cap. Pressed in on the valve (no keys in ignition) and it spurted some fuel. Tried it again and it dribbled at most. Turned the key to "on" and pressed in again, still only a dribble. Tried to crank it with a weak battery and it didn't turn much, but enough to say there should be enough power for the pump (correct me if I am mistaken). At this point I am thinking the stock fuel pump might have died which would be better than the Opti. I am charging up a battery jumper now. Are there any other tests I could perform to test the fuel pump? Trying to get a hold of a fuel pressure gauge.

Thanks for the replies so far, greatly appreciate the insight. 8-)


Back to studying for finals ... :knock:

[sweetbmxrider]

Spray some carb cleaner in the throttle body while someone cranks over. Once it starts, continue short squirts to keep it running. If that works, it sounds fuel related.

[FlyingDutchman]

Spray some carb cleaner in the throttle body while someone cranks over. Once it starts, continue short squirts to keep it running. If that works, it sounds fuel related.

Ok thanks for the advice, I'll post up the results when I get a chance. :-P

[greenformula92]

Sounds a little bit like a fuel pump issue

[FlyingDutchman]

Update:

Went to Sheetz and bought a can of starter fluid to test for spark. Hooked up the battery to a jumper since it was dead and tried to start it. Same result as last time, sort of started and quickly died, attempts after that just resulted in the engine cranking. Its like the pump builds a tiny bit of pressure but not nearly enough to continue running. Moved the intake elbow out of the way and sprayed some starter fluid in. Turned the key and it ran for a few seconds and died. Sprayed some more fluid in and it ran for a bit until the fluid was gone. It would appear there is spark.

Safe to say the fuel pump bit the dust?

[FlyingDutchman]

Called a local garage to get an estimate ... New filter and pump including the labor to remove the rear, exhaust and everything else in the way was $850 ...

So I asked, that's a top of the line pump right?

Well that's an AIRTEX pump.

Ok do you supply ACDelco or Delphi by any chance?

Well the Delphi pump itself is like $700 by itself so that would be about $1200 together.

Wow.

Rockauto has ACDelco listed at $290 ACDELCO Part # FLS1077 {#19179528}

[sweetbmxrider]

Or you could get a walbro/aeromotive/etc for under $200 and reuse your sending unit. This is also why people cut up their cars instead of remove the rear and exhaust. I would verify fuel pressure with a gauge personally and check for power going to the pump via the relay under the driver foot rest plastic. Did you try pulsing spray into the intake to keep it running?

[FlyingDutchman]

Or you could get a walbro/aeromotive/etc for under $200 and reuse your sending unit. This is also why people cut up their cars instead of remove the rear and exhaust. I would verify fuel pressure with a gauge personally and check for power going to the pump via the relay under the driver foot rest plastic. Did you try pulsing spray into the intake to keep it running?

Doesn't the walbro pump require some hotwiring kit to supply the correct amount of power? They weren't plug and play from what I read. Ill see if I can get someone to pulse spray while I crank it.

I can get a volt meter. How can I check to see the relay is transmitting power without disconnecting it?

[LTb1ow]

The fuel pump relay is under the left foot area kick panel, pull it out and verify it is clicking when you switch on the igniton. I would just pull it off, and then plug it back in, see if something changes.

You could throw a jumper lead across the connections so the fuel pump is just seeing power not going through the relay.

Otherwise, yea, a fuel pump is easy to do if you hack your car up, or a long job if you do it right. I would say a racetronix kit with the walbro is the closest and cheapest you will get to plug and play without it being a fortune.

[sweetbmxrider]

The computer only commands the pump to prime though.

Orange - Constant power from PCM BATT fuse #3 15 amp
Gray - Power feed to pump
Green/White - PCM relay command, hot when initial prime and running.
Black/White - Constant ground
Red - Fuel Pump Prime Connector. There is a stray lead by the pcm in the harness that you can jump 12 volts to and force power to the pump. If the pump doesn't run then, you can be most certain it is bad. Only other issues would be bad ground at pump or break in the circuit to the pump or ground.

[FlyingDutchman]

So it turned out the fuel pump was dead so it was replaced with a stock replacement. Thanks for the input/guidance 8-)

However, a new problem surfaced. After the mechanic had finished putting everything together he let it run for at least 15 minutes in the shop while he was doing some other odds and ends. He said the overflow tank was overflowing and the car was running hot. He said the fans didn't appear to be running. So he let it cool down and did it again with the a/c running and noticed the fans were running and the overflow tank didn't fill up. Took it for a test drive and at highway speeds (50+mph) it ran around 195*F and about 210*F around town (normal operating temps).

Drove it home last night 400miles and the temperature gauge stayed at a steady 190-200*F with no overheating issues. Although I did not just let it sit and replicate the problem.

Random event? Or possibly a bad thermostat like he was suggesting to me?

[sweetbmxrider]

Our cars are notorious for being a pain to air bleed. Try doing that first, ensuring the coolant is topped off beforehand before throwing any parts at it. The lt1's take a specific thermostat as well so make sure you get one for your application and not just a sbc one.

[greenformula92]

Could also be a bad CTS. That btw may not set an SES light. It will just give the ecm the wrong temp. reading