HCR13

iTrader: (5)

For a while now, I've been chasing down an rpm problem ( https://www.thirdgen.org/forums/tech...eleration.html ). I'm almost positive its my electrical system. Since its not the vacuum lines and fuel seems to be flowing. I just bought an Accel 120137 Distributor Cap. I'm looking for an ignition module aswell. Can anyone suggest what I'm suppose to be looking for? I've tried the search feature but I didn't find what I'm looking for. Terms I picked up: 4pin, 2pin, 8pin, multi point system, hei? I'm still an amateur but I'm quickly learning as I go. Can anyone suggest some part numbers, or images, or what exactly I need for a stock electrical set up on an 87 Trans Am TPI. Do I need the 4-pin electrical ignition module? Thanks for the help...

TheScaryOne

iTrader: (3)

Okay, there are two ICM's in the car. One in the dist cap, and I haven't buggered myself with the location of the other. But Checker has a listing for two different ones for these cars, at two different prices. The cheapest one is the one that seems to go bad the most often, and is the one inside the dist cap. Be sure to use the heatsink grease on it! It can BAKE without it. And it's usually heat and dried grease which causes it to go bad in the first place.

It's Neihoff part #DR411CS. I believe it's also called the two pin. The other in these cars is the (I think) 5 pin, and I think it's remotely located, and rarely goes bad. You can get the Accel version of the two pin, but.... Well. Sometimes you have to question if paying $60 more for a part you'll replace when you put in an aftermarket performance ignition.

Oh, and when you change it, be SURE which wire goes where. Elsewise you'll mess up your spark timing really really bad.

Apeiron

There's only one ignition module on the car, and the only location for it is under the distributor cap. They have 7 or 8 pins. Non computer applications use a 4 pin module, and some rare applications used a 5 pin module.

TheScaryOne

iTrader: (3)

Okay, I didn't know that there was only the one, but I can confirm on an '87 TPI car that the ICM is in the cap and is the part number that I referenced. I am currently running one on my car, which is an '87 TPI IROC.

But I did forget to count the number of pins in the other part. I just called it a two pin because it has the two exposed pins, which made sense to me. I completely spaced the two connectors.

Siggy

My 88 IROC is a 8 pin (normal) located inside under the cap, 2pins inside for the mag pickup, 1 outside socket with 2pins from coil & tacho (external coil) and the other socket is a 4pin going to the ECM. Accel also has a ignition module to suit PN. 35362.

HCR13

iTrader: (5)

Thanks for the feedback guys. I just went to the autoparts store and got one from there. It looks similar to the Accel pn 35362 (I'm not sure what the difference is, since the Accel says from 88 and up). I think it was one of the cheaper ones, only $35 or so. I'm going to install this one, and if it actually fixes my rpm problem, then I'll go ahead and spend the $50-$90 for a good name brand module. Again, thanks for the help!

AT4 T/A

I wouldn't doubt it one bit if it was that Accel module under the distributor cap. I had one in my '89 IROC, and it caused all sorts of stumbles in the engine. I ditched it in favor of an Autozone OEM piece and no more problems.

HCR13

iTrader: (5)

hhmm, is that so? I have the oem one aswell which I'm going to try that. How long did it take you guys to replace it? and difficulty. I was looking at it yesterday and it seems pretty simple, "hardest" part is keeping the wires correct and the angle so far into the engine bay...

AT4 T/A

Let's make sure we're talking about the same thing here.

To get to the module I'm thinking of, you simply remove the distributor cap. You'll then see a black plastic module about 3 inches long by 1 inch wide. There will be two sets of wires plugged into it.

Are we talking about the same thing?

In terms of difficulty, there's few things you're going to do that are easier. It's a total of 4 screws including the cap and module. Unplug the wires from the old module, plug them in the new one and you're done.

Bobby_80s

iTrader: (2)

My car has hesitation when you put it into reverse and drive. Once you get past 10mph or so it kicks into 2nd automatically, rpms shoot up and it runs much better. does this sound more of a distributor/ignition module,plug/wire problem or more towards and air leak or dirty fuel injectors?

any ideas?
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its a 1986 trans am v8 5.0 305 tpi fuel injected automatic. 102,000 miles on it. idle is a bit stumbly untill it warms up to operating temperature and then idle sets and is consistant and car runs much better.
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also it takes anywhere between 2-4 tries for the car to stay running. it starts but idle is rapid up n down and then quickly stumbles and dies. start the car right up and give it some gas and eventyually it will stay running on its own and liek i said is fine once it warms up.


im kinda stumped

TheScaryOne

iTrader: (3)

It's an easy enough job, I did it in under an hour with much swearing and cursing because I was having some issues lining everything up without burning the crap out of myself on my intake. Not a hard job at all. Don't strip the screws.

Bobby:
I dunno about your first set of issues, but the taking several tries to keep it running is what happened to me when my ICM went bad. I could crank and crank and crank, and it wouldn't run until I gave it gas, and wouldn't keep running unless I kept giving it gas. It eventually felt like running after ten or so minutes of driving. So yea, that might be your ICM.

Bobby_80s

iTrader: (2)

well part of my problem is bringing the car out from winter parking. workin on the fuel issue of it running lean.

but keeping it runnign was always my problem. like the car will start! but after a few seconds will stumble and die. try a second-third time sometimes four it will stay running but with rough idle and then warm up and it will be fine.

does this still sound partial to a ICM problem?

TheScaryOne

iTrader: (3)

For $35 can you afford to find out?

All in all, it's a part that's easy to replace, fails over time and heat, and can screw up how your car runs in a very major way. And the Neihoff one is cheap at you local Checker. And if that doesn't fix it, at least you can eliminate it as an option for $35.

Bobby_80s

iTrader: (2)

fair enough and its located under the dist. cap?

HCR13

iTrader: (5)

Ok, well I changed the ICM but sadly, it did not fix my problem. But, I do, however, believe that I found out what my problem is. The two set of wires that connect to the back of the ICM are what my problem is. From what I saw, they are suppose to be in some sort of plastic housing. That little plastic housing is gone. Now, its actually a couple of plastic strips in some green "goo". Now, does anyone know how to replace this wires without having to buy a whole new distributor? For the moment, I just wrapped them in electrical tape() until I figure out what to do. Check out the pics to see what I'm talking about...

HCR13

iTrader: (5)

*edit: ECM=ICM (pics)

AT4 T/A

How did that happen??? I'll bet you're onto something here. The connector isn't melted, and that's the green goo, is it?

I guess how to fix it would be the next issue. If it were me, I'd pay a visit to my local junkyard and cut one off a TPI car. If that weren't an option, I'd go to a local dealership or repair shop and see what I could find.

Does your car have a history of overheating? There is a grease that should go in between that module and the metal disc where the cap connects. This grease helps to dissipate heat and keep the module from being damaged. Make sure you get some.

Please let me know how this turns out!

HCR13

iTrader: (5)

I have no clue how it happened. I replaced the water pump around this time last year, since then, I've had great cooling on the engine. It also has a good aftermarket radiator. But its not as "greasy" as I'm thinking it should be, as the pic shows, its mostly dirty. What is this grease stuff called? There aren't any TPI cars in my junkyards, only V-6's. I'm still planning to take it to the mechanic Tues and talk to him about it. I couldn't figure out how to take the rotor off or the green sleeve to see exactly where the wires were connected...

TheScaryOne

iTrader: (3)

There wasn't a connector on mine either. Just green goo. I think it's dielectric grease, and the two colored connectors ARE the connectors. The new part should have came with a packet of grease to smear on the side that touches the dist. That stops the unit from overheating.

HCR13

iTrader: (5)

Ok. I just don't explain what the broken plastic strips in the goo where. I bought a separate pack of dielectric grease which I coatted every metal piece touching the disk. Tomorrow I'm going to the junk yard and looking at some of the ignition modules there...

HCR13

iTrader: (5)

Well, results are still confusing. Some of the older Thirgens did not have a plastic housing, but the later ones (87+) did. I'm going to guess that mine did have the plastic housing. I'm going to go to another boneyard tomorrow and check those out. All the F.I. cars were v-6 if that helps...

AT4 T/A

Try the dealership or a local speed shop. TPI's should be plentiful, since people have been putting them in hot rods forever.

Maybe it's time to think of something else. Autozone doesn't have anything you can use to fab something up?

HCR13

iTrader: (5)

I got a new Accel dist. cap and installed it today. It made a huge difference. Didn't totally get rid of the problem, but 95% of it. I took it to a mechanic and he said that it sounds like the wires are arching. It has regular 7mm wires, but I was planning to replace them with Accel 8.8mm next paycheck. I also want to go ahead and replace the rotor, does anyone know how to take the rotor off? It seems to be riveted on there and I'm not sure how to pop it off?
As far as the two wires on the back of the ecm, I got an extra wire hookup with the plastic housing from a donor distributor and attached it to the two bare connections. So far its working. I'll find out more tomorrow...

TG Goose

the rotor should NOT be riveted on. Its probably just a hex head screw, probably 8mm or such. unscrew, remove, new one can only be installed one way, screw down and put cap back on.

HCR13

iTrader: (5)

thanks. I'll go ahead and order one and when it arrives, look at the replacement for further analysis. But I still plan to get the wires first. The inside terminals on my cap were pretty corroded and worn from 20yrs of contact with the rotor, the new one made a huge difference...

Trans Am Concep

Guys: Looking for tried and true informed opinions: I'm currently restoring two '91 GTA convertibles that house the 305 TPI's. On one I replaced the distributor with a new MSD system. The other is in such great condition, very low miles, that I just want to replace the ICM, cap and wires. At the moment I'm looking at a Mallory 612 and a Duralast DR140 (from Autozone). The Duralast is the least expensive but is warranted for the life of the car. The Mallory is more expensive but apparently is not warranted. Are there any advantages of using the more expensive ($67.99) Mallory over the less expensive ($46.99) Duralast? Thanks in advance for advise/opinions.

Ken
T/A Concepts

Irockirocs

What takes the five pin? I think my 86 tpi 305 camaro needs a crazy icm