felo72

Let me give an example first, say your driving your car, and it's running great, no signs of a problem, your battery is a little low, between 13 and 8 volts, you pull into a gas station, grab a pop, come out to start the car and it won't fire. It turns over, but it seems like your not getting any spark, this is on a TPI model by the way. You let the car cool down for about 15 to 20 minutes, try it again barely turning over because the battery is about drained and it finally starts and runs a little rich. Could this be from the ignition module getting hot?

Free Bird

iTrader: (1)

I would also like to know how can you tell if one is bad?

bluegrassz

iTrader: (3)

take it off and have it checked at advance or autozone, or whatever part store is in your area. They can check it in a matter of minutes.

Sena'sIROC

First you need to determine it's not getting any spark. First check at the plugs, and check at least 3 plugwires. Not getting any spark from there, move on to the coil wire and test it. Should you not get any spark off of the coil wire, there are 3 more possibilities:

1) Check the pins for power on the four connector that plugs into the ignition module with a test light or a DVM. You should get 12V.

2) Take the cap off and take out the ignition module that is fastened down with 2 screws and take it to Autozone to be tested. Have the guy behind the counter test it 100 times and watch it as it gets hot. If it fails that's your problem.

3) While you have the cap off, test the pickup coil leads with a DVOM for resistance. It should read 500-1500 Ohms and infinite reading to ground. You get less than that or more than that and your pickup coil is going south.

Hope this Helps, been there done that.

Brian P
89 IROC-Z 355

Sena'sIROC

By the way, if you can test them under heatsoak conditions(a.k.a when it happens to ya) then that is the best way to determine.

It'll only worsen from here if you do not resolve this issue. The car will probably shut off in the middle of driving or continue getting those no start conditions.

felo72

In other words that is my problem and I'm in the beginning stages of it? If so thanks for the help.

TomP

You might want to just replace the thing anyway, if it's the original (old) unit. Holley makes a high-po replacement (891-103), you can get it from summitracing.com for $60. Accel also makes a replacement, if you call Summit I'm sure they could get you a part #. Replace the $12 pick-up coil with a stock unit while you're in there (no performance pickup coils are made because the thing can't be improved, it senses a magnetic field).

felo72

Thanks for the advice, I changed both last night, the car ran great, but still had the same problem. I changed the alternator, and after driving for awhile the car started to hesitate and I blew an instrument cluster fuse again. Although I came to find out that the alternator is wrong. The car is an 86, but the EPROM is an 88, so the voltage regulator could be different, causing me to blow a fuse. I checked the part numbers for both years and neither one match. Check out the thread under timing?, thanks.

Oh, as for Summit having the parts, I had both of them here in stock at Summit, but Autozone was cheaper than my cost, and I'm running out of money.

Ricktpi

The voltage regulator is inside the alternator & really has nothing to do with the EPROM. If your regulator is bad & its not keeping the voltage between 12 & 14 volts that may be the problem, but not likely. If you are blowing a fuse its because of too much current flow, e.i. short, bad electrical component, etc. not too much voltage.

felo72

I know the voltage regulator is in the alternator, and has nothing to do with the EPROM, I was giving information about the car. if it's wrong, too much voltage, or flow, could follow through the system. If it affects the coil, the coil is followed back to the gauge cluster fuse, causing a fuse to blow. Even if the coil isn't the part being affected by the voltage aspect, there are many more parts that are connected to the gauge cluster, look at a wire diagram and you'll see. Which once again could overload that part causing the fuse to blow. If it isn't the alternator, than what could it be? I already checked the part numbers and noticed I have the wrong one on the car. Plus I had the old alternator checked and it had a short in it.

Sena'sIROC

Okay man, you did tell me what it was doing. You did tell me what you've done about it, but you haven't told me what year/motor/fuel injection you have. That's a good start.

Since you mentioned chips I will assume that this is a TPI car. So under what pretense did you decide to use an 88 chip?

I would lean towards the fact that you have a ground issue on your hands. If you're blowing fuses in the fuse block then you might need to break out the service manual and start looking at your ground. A messed up voltage regulator in the alternator can cause some weird problems, like some that you have mentioned. At this stage in the game, don't throw anymore parts at it until you've diagnosed the problem. Otherwise, it's like pi$$ing in the wind. Have access to a shop? If so, put it on the charging system thing and see what it is doing.

So here's my advice, have patience, throwing parts at a car is instant gratification but oftentime a waste of cash and time. Diagnosis of a problem is time-consuming and frustrating.

It's a matter of what you are in it for.

felo72

Thanks for the reply, I didn't mean to come off the way I did in the last message, it's been a very frustrating road. I worked on it last night and figured out I was wrong, the alternator wasn't the problem. Getting back to you about what I have, the car is an 86 IROC, the person I bought it off of put a 350 TPI in place of the 305 TPI without changing the computer or EPROM. I started working on it to make it run better and that's where it all began. just about every sensor and electrical part is new. I kept throwing a code 33, and the computer constantly went in and out of learn mode. The car also overheated, after a couple of weeks of troubleshooting, and having the guys here help me along the way, I discovered the EPROM could be the problem. The code 33 was brought about because the 350 was letting more air in than the 305, plus he changed the injectors to 22 lb/hr, the computer read it as running lean, but the AutoXray said it was rich. Before I heard about the EPROM, I changed the MAF relay, but didn't know which one it was, plus Auto Zone had two but couldn't say which one would fit the car. So I took my chances and bought one and installed it, and it drove great, then I blew the gauge cluster fuse. So I bought the other one and tried it, and the same thing, fuse blew. I've even disconnected all of the relays, had the computer out, had the cluster out, and disconnected the wiring from the brake relay all at the same time and it still blew the fuse. Finally I tracked it down to the air pump and disconnected the to connectors and the fuse quit blowing. Hooked everything up and the car ran fine, but when I would turn it off and try to start it, it would turn over all day but not fire. So from reading stuff on the board I figured it could be the module or coil, so I changed both of them, plus retimed the car to spec. Same thing still happened, it just would not start, so I figured the alternator wasn't charging, I took it off had it checked and there was a short in it. I changed it and the car ran fine, drove it for 40 miles, 20 on the hwy, turned it off, and it still wouldn't fire until I let it sit for 10 to 15 minutes. Once I finally got it started, it ran like sh*t and the damn fuse blew again. And that brings me to yesterday, I changed the alternator again along with a new battery and still can't fix it. Sorry this is so long, but I just wanted to give the info, if you could help or have any suggestions, I would really appreciate it. Thanks again.

Sena'sIROC

Code 33: high voltage at MAF sensor.

This is a good start. See how a little background can make a big difference?

Awesome. Now, let's look at it like this, whoever swapped in the 350 TPI motor hacked the wiring a bit.

Let's talk about ground. Now, you should have two 2 ring terminals, forget the color I think tan w/ black stripe(?) bolted to the back of the passenger's side head with a large ground strap secured to the firewall. The two 2 ring terminals provide ground for the ECM and the MAF.

If one of those aren't grounded you might have some issues at hand.

In the meantime, I'd like for you to unplug the MAF sensor and try to start the car.

Let me know the results of this as soon as you can.

Brian P
89 IROC-Z 355

felo72

Thanks, I'll either work on it tonight or tomorrow on friday. That's definately a start.

felo72

Oh, one more thing, if I unplug the sensor, do you want me to try another fuse to see if it blows? If it doesn't, more than likely the ground should be the problem, maybe? The two ring terminals, are they underneith the heater core lines? Thanks again.

Sena'sIROC

The two ring terminals should be back there by the heater core. One should be tan w/black stripe I think, and the other I forget what color. They should be mounted on the back of the pax side head with a large groundstrap secured to the firewall.

Don't try starting it with a new fuse at first. I'm trying to figure out if this is a MAF deal or not. So just unplug the sensor and see if it starts. Then swap in new fuse, see if it starts without the MAF sensor plugged in.

Lemme know what happens.

Brian P

felo72

Ok, I checked the ground and the two ring terminals and they are all there hooked up. I didn't mention that I already changed the MAF sensor, last night I did discover that one of the relays for the MAF sensor, the only relay I didn't change was bad, so I changed it. Started the car and went for a ride, I noticed my volt gauge wasn't where it should be, actually I couldn't get it to go above 8 volts, and the car would idle up and down and when I pressed on the gas it would vibrate and have just a little backfire. On my way home I pulled into AutoZone to have them check the alternator. When I went out to start the car it wouldn't even turn over, we tried to jump it, and even put another battery in it and when I turned the key it automatically killed the battery. I ended up changing the battery and alternator in their parking lot and still had to tow the car home. I have to have a short somewhere. I think once I replaced all three of the relays I finally got power to something that didn't have it before and it's shorting out like crazy. Is there a fusable link by the starter that could be causing it not to start? I mean nothing, not even the clicking noise when your battery is low.

Sena'sIROC

There's a fusible link right behind the pax side headlight. Check it to make sure that it didn't fry on ya or shorting against something...

Brian P
89 IROC-Z 355

felo72

Thats not the one that comes off of the positive battery terminal is it? If it is, I already replaced that one.

felo72

Ok Sena, here's the latest:

The Demon left and came back in another form. I did nothing from the last time I wrote and had the car towed home because it wouldn't start or turn over. I went out this afternoon and just thought I would try to start it. I put the key in, turned it once, two cranks later the car started right up. Now it didn't run well, but it atleast turned over this time. I was told the fuel injectors could be leaking and causing the engine to flood, causing me to not be able to start the car directly after running it, but it not cranking the last time still has me puzzled. It's possible, but I still can't pin point where the short is causing the gauge cluster to blow also.

Oh one more point, I turn the ignition on, and heard the fuel pump prime, then started the car. Turned it off and turned it right back to the on position and no prime noise. Went to turn over the car and it started. I tried this a couple of time and it ran. Not well enough to drive but it ran. I don't know now...

bluegrassz

iTrader: (3)

I found out my problem with code 42. I broke the plug end out of the ignition module. I replace the module, but there was a broke piece of the old module under the rubber seal on the plug in.

My car would not start, I retimed it, check every hose, wire, fuse, and everything.

I just goes to show that is usually is something simple or something over looked.

oh yeah. happy b-day felo72. mine is the 29th.

felo72

Hey thanks!