green95vert

iTrader: (2)

OK, I bought the car after it sat for a year. I seafoamed it, descreened the MAF and cleaned the wires in it with alcohol, and tossed a new fuel pump in it (Walbro). Ran great, took it to work and reflashed it with a newer calibration, it said it has an 'unknown calibration' so I put the newest one it had in it. New plugs and wires, MAP, CTS, IAT sensors. It said my new speed limiter was 118 after I reflashed it, but the other day I raced an **** and went to 135 before we shut down (had him by about 3 cars btw). So here's my problem...I'll drive it for about 1-2 hours and it'll spit and sputter like its not getting fuel, I'll let it cool for a few hours and it'll fire up and drive perfectly fine. When I start it cold, the fuel pump screams, then quiets down after a few seconds when running. I don't know if this is normal or not. Here's the possibilities I'm thinking of:

1) O2s - Looked fine when I borrowed the Tech II from work, but hear its a fairly common deal with LT1s

2) MAF - Maybe I ruined it with cleaning it since it looked dirty, yet another GM thing I hear

3) Injectors - I worked on an older 3.1 Cavalier that when the injectors got hot, 1 of them shorted and killed the car after a few minutes.

4) ECU - Maybe I reflashed it over an aftermarket chip, I assumed it was stock when I bought it cause everything else on the car was stock too. Hence why I might have no speed limiter also.

5) Ignition Module - Getting hot, breaking down, making it run like ***.

6) Optispark - Isn't the Crank Position Sensor in the Optispark? Another tech at Saturn said a CPS could do this and since I also hear its in the Optispark...yay

Any ideas? I don't feel like tossing any more parts at it cause most everything thats left is not exactly cheap (nothing crazy expensive tho either).

9formula4

iTrader: (5)

I would try the ICM first off. But if it is a 95 there is NO chip in the thing. You have to flahs the PCM when reflashing it.

dhdenney

iTrader: (53)

95 doesn't have CPS and they are on the driver side bottom of the timing cover, not in the opti. Flashing the PCM doesn't "combine" tunes. Whatever you put in there has overridden what was in there. Fuel pump shouldn't ever scream. When I turn my car on, I can hear it prime up and then I start the engine, but I never hear it after that over the exhaust. I know I didn't help but we've knocked some stuff off the list.

green95vert

iTrader: (2)

I understand it doesn't combine them, if that was true there wouldn't be any point in reflashing it. I was just sayin maybe the ECUs messed up cause on the TIS2 it said my new speed limiter was 118, which there is none. Even a Walbro 255 shouldn't be loud? Where would an LT1 get a reference for where the crank is at if theres no CPS?

So what angle would you go at this thing from? Thanks a lot for all your help so far, I'll prolly go with the ICM next since it won't break the bank too much.

Forgot to mention, no codes when it does this, and I had a code 16 when I got it (Low-res BS), but haven't got that code, or any code for that matter, since then. Also, the connector to the MAP is broken but the pins go all the way in and seem to seat just fine.

camar0corey

iTrader: (22)

The fuel pump should only make a noise loud enough to be heard for about one to two seconds. You are saying yours is still making racket after the car has turned over?

I know Napa can test the ICM, don't know about the other parts stores. Well only some Napa stores have ICM testers.

green95vert

iTrader: (2)

Only for about 3 seconds after it starts, I wasn't sure if it was normal or not. I didn't know NAPA can test them, we got 3 of them in my town so I'll try them, thanks for the info.

edcmat-l1

iTrader: (10)

If you have access to a Tech2 I'm sure you have access to an oscilloscope. So why go throwing parts at it when you can properly diagnose it using an o-scope and a systematic approach?
As for bench testing the ICM, if its a heat related problem, and it IS the ICM, testing it at NAPA or anywhere else will do you no good if you cannot duplicate the heat and run time cycle.

dhdenney

iTrader: (53)

Well when you posted this I didn't know which angle to take on it but I just wanted to establish that whatever programming was in there is gone once you do a flash.

4) ECU - Maybe I reflashed it over an aftermarket chip, I assumed it was stock when I bought it cause everything else on the car was stock too. Hence why I might have no speed limiter also.


As far as the ICM, what I would do is when the car got warmed up and started acting up--I would pull over and take the coil wire off and see if the coil was possibly cutting out. Take a buddy and have him crank it while you watch it. Maybe make an observation before you took off for the day to see what it looked like. You might see a change in the output of the coil and you might not. It's not gonna cost anything and I would hate to see you buy a new ICM for $80 and that not be it. As far as the MAP goes, I wouldn't really base my decision on the fact that the pins are in there. You'd really have to see what the PCM was seeing on a scanner to determine if it was working. However, in my experience, if the MAP is off, then you'll notice it from the get go.

96capricemgr

iTrader: (1)

The ICM should have thermal paste on it, when removed few replace that paste. I would start looking at that for the poor running after a few hours.

A "technician" is going to have a hell of a time modifying a car though, what they teach you is NOT what you need to know to modify a car.

edcmat-l1

iTrader: (10)

A "technician" will be able to diagnose an electrical problem using the same equipment and test procedures as used on virtually any other car.
Being modified only makes it a little more difficult, as you have to wade thru the **** thats abnormal. But all the basics, both mechanical and electrical still apply.

Blackbirdws6

iTrader: (7)

My ICM was giving me the same issues. It would make the car sputter and eventually just die. If I waited, it would refire like nothing happened. However, it didn't take nearly as long to have the problem as yours so I wouldn't say that's your issue. My car would either run fine for 40 min or only 15 min. It's not a cheap piece (~$80) so try to see if everything else is alright before you go a buy a new one. Good luck.

-Brian

dhdenney

iTrader: (53)

Paste on the back of the module itself? Shimming the bracket can create an airspace between it and the head. Wouldn't be a bad idea to do.

96capricemgr

iTrader: (1)

In stock form there is paste between the module and bracket, between the brackets and between the heads. That orientation works fine for me, I know some guys do put washers between the coil bracket and head for an air gap, still then you need it between the brackets and module.

Honestly though that spot on the head is fairly cool as it is where the water feed is, I think that may be why GM did it the way they did.

Far as "technicians" they are trained to replace parts and bleed money, the later they are not openly taught but that is the end result. So very few have a true understanding of the processes and science involved which is what allows some enthusiasts to master their cars and really helps diagnosis.

I will take Datamaster over a scan tool.

SLawson86

iTrader: (8)

not flaming your comment 96caprice, but datamaster is **** compared to a tech II. and to the others, the oscilloscope on a tech II is way too slow to catch a glitch. (personally i use a UEI scope) also technicians are not "trained" to replace parts. you have "parts changers" any damn place you go. to the poster, a walbro shouldnt scream and raise hell as you are stating... mine is fabbed up out of the bucket and still is really hard to hear. sounds like an icm prob or an opti problem. there are a bunch of variables in this equation, but it is really hard to shoot solutions without a snapshot of data. being that this is an intermittent problem, i kind of doubt the MAF although i strongly disagree with descreening them. my suggestion to you is put a fuel psi gauge on the car, and set a scan tool on snapshot when it usually acts up.

green95vert

iTrader: (2)

Saturn is stupid here in Terre Haute, we had to have a fellow technician buy a torch to use, much less talk the owner into an oscilloscope. Wish I had access to one.

Last night it took only 1/2 hour so it is getting worse, the night before it took an hour. Maybe it could be the ICM? If so, does an MSD box replace the ICM just like it does on HEI? If thats the case I'll just snag an MSD box. I took the ICM off and there is no paste on it like someone else wiped it off or whatever, I'll go buy some, it can't be too expensive.

I would get a snapshot of data, but theres no MIL and I had a hard time walking out the abck door with a brand new TechII and CANdi module (even thought I didn't need it) without getting my head ripped off, so a snapshot is almost impossible to get on this thing.

I was modding my old IROC long before I became a technician so it doesn't really matter whether they "teach me not to mod cars" or whatnot.

Thanks for all your help though, I'm assuming its the Opti or the ICM. Is the GM Performance Parts Opti a good piece or should I just go to another dealer and get a factory one? (I get a lot of GM stuff at cost). As far as the ICM goes should I just get an MSD box, chances are I'll get one in a few months anyways, any suggestions? I was looking at the Fireball HI-6R last night.

dhdenney

iTrader: (53)

As far as I know, you are stuck with the factory ICM.

green95vert

iTrader: (2)

Well that sucks, so the MSD box piggybacks the ICM (or w/e you wanna call it)??

C_Rules

iTrader: (7)

sorry for the useless post just had to say i enjoyed the LT1 (eltie juan) had me wondering for a second there.

SLawson86

iTrader: (8)

well since thats the case, get an icm first. i hate to throw parts, but i believe at cost they are around 25-30 bucks. and for the opti, i use a factory GM one, havent had a problem yet. good luck man, keep us posted. where is your location, if it is near where i am located, you are more than welcome to use my tech II, my Solus, or the MDI... let me know

green95vert

iTrader: (2)

Lower West Indiana is where I'm at :-( Thanks for the offer though SLawson86.

Me and my friends always called their WS6 and Z28 Ellis Juans, so mines the Eltie Juan haha.

So before I go to bed, should I get a ICM or would a Fireball HI-6R replace it?

Thank you all for your help, I almost got a FPR, MAF, and O2s just cause tahts what other techs and I thought, but after reading this the ICM and Opti make much more sense.