Okay guys, I give up. I am really frustrated. I can't even get the darn thing to idle. Here is a turbolink file of the 20 seconds I could get it to run. (right click and select 'save as') art_84gn.ecm Maybe someone can see something I missed. The car is a completely stock 84 GN, It started running like crap all of the sudden one day when I went to go move it. The car is currently undergoing an interior restoration, so lately it only gets started about every other week. I checked the plugs, four were fouled. I replaced the plugs and wires, and they fouled again, car wouldn't run. I checked fuel pressure, steady at 30lbs static. I did a leak down test, lost only 2lbs after four hours. I replaced the coil pack and plugs, again same results. I then upgraded to the 87 CCCI module (the 84 was too pricey), replaced plugs, same results again. I then installed a known good set of used injectors, replaced plugs (parts guy is starting to wonder where all those plugs are going!). Same results, won't run and plugs fouled or wet. Other things that have been replaced recently: O2 sensor, MAF hose, all vacuum hoses, PCV, fuel filter. Any suggestions on what to try next are GREATLY welcome! Preferably, before I drag the car with the tractor out to the back fourty into the weeds.
Check your firing order! The coil pack you are using is a 1987 unit, and the firing order may be different than the original coil pack you replaced it with. You MUST use the 1987 firing order when using the conversion system.
-John Spina
http://www.casperselectronics.com
http://www.casperselectronics.com/cobra.htm
I am using the 87 firing order. I verified I had it right twice now. Like I stated, I was able to get it to idle for about 20 seconds, not quite smoothly, but as soon as I gave it a hint of pedal, it died, and wouldn't start again. Plugs fouled and wet. Maybe someone could look at the turblink buffer file and read something from the numbers and tell me what I should look at?
"The car is currently undergoing an interior restoration, "
Arthur,
Did you by chance disconnect any of the wiring while working on the interior? Maybe just bumped something that may have been loose? If it's not that, I'll keep you posted. I'm currently trying to get a friend's 85 GN running right. It wouldn't start at all, but a new crank sensor and coil fixed that. But it has a terrible hesitation and popping thing happening now. Good luck
UPDATE:
Okay, I checked the CAM sensor B terminal, stayed at 5.04v, regardless of crank position, never changed. I disconnected the sensor, and checked the voltages at the connector leading to the ignition module, I had the following, A=12.4V, B=5.04V, C=0.03V.
Can I assume there's something wrong with the wiring? I double checked my 84/85-to-86/87 conversion wiring, it's right ( I converted AFTER I was getting the no-run problem, to eliminate a bad module). Should there be 5V or 0V there? Or should I just assume a bad cam sensor and replace it?
Only question now, is it cam sensor, or wiring?
UPDATE #2:
I have removed the cam sensor. I took it in to my workshop, applied 12V+ to A, and '-' to C. I read 0v at B, regardless of position. I removed the top, but the "revolving cup window" was still in place. So, a new cam sensor is on order for $44. None of the local parts stores had one in stock. Not sure of the brand, but the local chain (Ridge & Kramer) only uses name brand stuff, so I know they're good. As a side note, AutoZone wanted $109.99 for it!
I should have it by Wednesday.
That is not how you test it. You need to provide a small positive reference current to the sensor output, using a 10K resistor between A and B. Then you look for a negative transition on the B terminal when the window is open, and an open circuit when the window is closed. Also, don't use a test light; it can damage the transistor in the Hall chip within the sensor cap. I've been thinking about some sort of plug-in tester to check the CAM and CRANK sensors, something that can plug between the coil module and its harness connector. The plan is to provide a digital display that can show cam and crank signal counts so you can troubleshoot the system. If there's enough interest in it, I will pursue that. Target cost is around $80 or so for a nicely made diagnostic type unit. Any feedback??
-John Spina
http://www.casperselectronics.com
http://www.casperselectronics.com/cobra.htm
John,
I myself have never had a problem with either sensor, except for the one that I broke, and I knew that was bad. BUT, an inexpensive tool would definately be good to have especially if you work on them alot, and $80 sounds like a good price.
Brian
Okay John, is this the right way to test the cam sensor?
I applied +12V to A, +5V to B, and GND to C. Through it's revolutions I only get 5.04V no matter what.
Ouch! Don't apply 5 volts to B...you'll destroy the sensor! Here's how it works: A gets 9-12VDC, C gets the ground. B is a NPN transistor which goes to ground when the window is open, and B opens (high impedance) when the window is closed. To test, you need a resistor, about 10K, between the A terminal and B terminal. Then...you apply your digital volt meter between B and C. Rotate the sensor shaft until the window is closed. You should see 9-12VDC when the window is closed, and close to zero volts when the window opens (0.1 to 0.6 volts typical). Never NEVER apply voltage to the B wire, and don't use a test light to test it since the switching current in the internal transistor is maybe 1/10 of an amp. Test lights generally pull more current, and that will destroy the transistor.
Hope this helps,
John Spina
http://www.casperselectronics.com
http://www.casperselectronics.com/cobra.htm
John,
Why don't you tell him the best way to test the cam sensor? The best way is to buy one of those cam sensor tools. Excellent device. Someone on this list makes and sells those things. If only I could remember who. Oh yeah, it is Caspers Electronics. http://www.casperselectronics.com
Ever hear of them John?
Of course you have. They are you. It is a very useful tool for setting the cam sensor.
Brian
Art,
Well, I am not John, but I think I know the answer to your question.
You should not apply voltage to the B terminal. That is the 5v reverence that the ignition module sees. One way to test it would be to apply 12v to pin A and Ground to pin C and read the voltage off of pin B with a volteter or even a test light (led). When you spin the sensor (assuming it is out of the car) you should get a sqaure wave, on off, 0v 5v, signal. Don't spin it too fast though, or you meter may not catch it. You can also test it in the car if you have a really nice meter that has a scope function.
No need for the cam sensor setting tool, just a voltmeter and some knowledge of how the thing works.
Mike Gloff
If you need a cam setting tool, Kirban Performance Products in PA. also sells them!good luck on getting your car straighted out.
hey, I had the same issue on my 84gn it would run for 30-45 sec and stumble,putter and die. after swapping to new disc style inj, new 02 sensor, numerous sets of plugs, blood, sweat, tears, and quarters in the swear jar I found that some corrosion in the ecm connector that had the fuel inj circuits in it.(found when I was pulling apart my interior, go figure) I only post this as my windshield was leaking on the pass. side and when the guy came to install a new windshield he mentioned that this was a common issue with this car(his 2cents not mine) but no doubt had allowed the water to get into and start to corrode my ecm connectors. This event happened @5yrs ago and since then a have been "happily" working on my 84GN. I guess that all depends on what day and what part of the car I am under.
Thought I would update anyone who was following this thread. But first, a little history.
I originally got the car from my brother, (he owed me money, and I am still on the losing end of that deal!). It had sat for several years due to a blown transmission.
I overhauled the transmission three years ago. But no oil pressure. Taking apart the oil pump to pack it with vasoline I found very heavy grooves worn in the plate, which I machined flat and re-installed. Everything ran well, I was able to drive the car, so I thought "Great! Now to work on the interior."
As soon as I drop the seats off at the shop, the motor decides not to run anymore. So over the next couple of years (I am also working on remodeling the house, new kid, college at night, a Dad that insists that I work on his 87GN and his house instead of my projects!) so the diagnostic process takes a while to complete.
I kept getting plugs that shared a coil to foul (I later found out it was coincidence), even after replacing the coil pack, so figured it was the module itself. Upgraded to the module to the 87 version (84 replacement was expensive!). Still the same problem.
Close inspection showed many cracks in the headers, had them fixed.
After lots of reading I knew that it couldn't be the crank sensor, because it sort of wanted to run, so I started looking into the cam sensor as the culprit. New cam sensor and plugs (I have gone through several sets of plugs because of the fouling problem). Still no success.
Then Dad asks me "How old is that gas?" Pause from me as I think dumbly.
I then pump out about 5 gallons of very yellow varnish. Add 5 gallons of AGRI-Plus 90 (our local gas station has a pump that has a gasoline that has additives for lead replacement, detergents, stabil, anti-varnish, etc., etc., very good for older equipment or stuff that doesn't get used a lot) and new plugs, again. Now it tries to run if I feather it. Acts now like it is out of time. But I was very happy! This was an improvement over the last few years.
Removing the front cover showed the worst timing chain I ever saw. Beleive it or not, but all of the nylon was intact, but with deep grooves worn in it, as well as in the crank sprocket. The chain was so bad that when I "squeezed" it in the middle, they could darn near touch!
I am now about 45 minutes away from completing the chain replacment (hopefully this weekend).
Sorry for the long post, I just wanted to share what I went through during the last few years. The seats are all finished, and my wife has approved fundage for the door panels to be redone! Maybe soon I can enjoy the car from the inside instead of the outside!
Art Keene
84 GN - all stock (for now!)
turbo84gn@yahoo.com
Another update: Timing chain installation is complete, but still doesn't want to run right (see previos postings for history of problem). I am certain that the timing chain is on right, I had my Dad and my brother double-check me. I have uploaded a saved turbo-link ECM file on my homepage at http://www.geocities.com/turbo84gn/cars/cars.html
I can get the car to run if I feather the gas at about 1400 rpm, but I get a steady backfire. If I let off the gas it will die. I'm ready to pull it next to the road and put a FREE sign on it.
Any suggestions and what to look at next?
Arthur,
I wouldn't give up just yet, but if you do, could you leave the keys on the front seat, along with a signed title, and tell me where you are going to leave it?
But seriously, where are you located. Maybe someone near by can help you diagnose it, or tell you a good shop to bring it to, if you don't mind someone else working on it. At this point I don't think you'd mind.
How did you swap over to the 87 coil module? Did you rewire it, or buy the wiring adapter? Have you tried running a real good fuel injection cleaner? If the fuel was that bad, maybe the injectors need to be cleaned or replaced.
If it is starting, and running, even poorly, then it sounds like the crank sensor may be ok, and you are getting something from the cam sensor. Try unplugging the cam sensor while the car is running. If the cam sensor is out of adjustment, then it should clear up some. If I were you, I would wait on doing the interior over, unitl it is running right. There's nothing so frustrating as spending money on a car that won't run. I would concentrate on getting it running, then when you are sure that you've got it, then work on the interior again. Focus your money and energy on the important part first. Gotta get back to work. Hang in there.
Brian
I think I finally found my problem causing the car to run rough (read through previous posts to see history of problem).
It turns out that a new ignition module was bad. Even though I had spark when connected to a grounded spark plug, it wasn't enough to fire the timing light. I moved the connections on the coil to make sure it wasn't the coil, but problem moved with the connection. I also swapped plug wires.
Question: This is an 84GN that I upgraded to the 87 C3I module. Can I assume that if I made any mistakes on the wring conversion that it won't run at all? The fact that it runs (looking at the wiring schematic) should mean that the wiring is correct?!
P.S. (no flames please) My Dad was trying to help and picked up the module for me one weekend at (ackkk!) AutoZone. (He wanted me to get the car running in time so that we could go to a car show togethor with our GN's) After looking through archives, is there anyone that has a working AutoZone module? I obviously can't return for refund (had it too long), but I can exchange it.
The coil pack and ignition module that I bought from autozone seems to work well. It is a Wells and everything is fine except that the coil pack doesnt entirely screw down to the module, I think there was a spacer that I didnt buy, but the connections are good and although the car hasn't had any miles put on it the parts from autozone work for me.
The tech at autozone tested the ignition module and it tested good. (I was impressed, they have quite the little collection testing equipment!). I had a GM dealership mechanic in the store overhearing us tell me yesterday that a crank sensor growing old and week (magnets) can cause a misfire condition, not picking up all the windows on the crank. I assumed that if it ran at all (even poorly) that that usually meant that the crank sensor was good. Autozone offered to test the sensor for me. Any input?
Hey, I am new to this site but not new to these cars. I have been working on GM cars for 25 years, the cam sensor must be installed correctly for these cars to start and run right. Well try to come up with more info later
Arthur,
Damn..I feel bad for ya. I'd buy ya a beer if i could. This is probably something you already thought of, but I tell myself this when im about to give up:
4 things all cars need MINIMUM to run:
1) fuel
2) air
3) spark
4) exhaust
If it runs - even like crap..it's gotta be spark. It will run on 6 cylinders, 5, even 4 - but if it starts at all - you know you have fuel, air, exhaust, and some sort of spark...so it's gotta be timing/spark related. Focus there. Think what changed since it last ran right? To get spark you need power & ground. If the coil is making a signal, check your engine ground. Is your SES light on? Any codes set? Wires shorting? Are your injectors working properly?
Constant wet fouled plugs mean 2 things to me:
Weak ignition or too much fuel. Doubt your fuel delivery increased to 4 cylinders and not the rest - check that coil & module. Go back to the '84 for testing if need be. It's gotta be spark...
....I've seen a clogged cat converter COMPLETELY screw up my GMC S15...it is only a 2.8 6 cyl....but it sat for over 2 years without being started. the problem I had sounds identical to what you're going thru now....testing sensors and replacing parts when the whole time it was the stupid cat...
sounds like a maf sensor to me!