Ignition Troubles - Page 2

patkeefe · 04-19-2005, 03:32 PM

All of the electrical tests check out ok. I couldn't see squat on the scope. As I'm colorblind, I had my girlfriend look at the wire from the dist. She says it's not green. I'll have to yank the dist tomorrow and check it out better, if necessary.

By the way, the sticker for the pinout on my CDI unit is mirror imaged from left to right. The one which is 31?ground was backwards on my sticker, but ok in all other literature. Nice of Bosch to do that.

Early_S_Man · 04-19-2005, 06:10 PM

Pat,

Yep, the pinout on the sticker is looking into the connector of the CDI box with the mounting flange sitting on the hand or table ... not terribly useful when you have the cable unplugged looking for a trigger signal! That harness could use a plastic tag with the pinout on it!

. 31/1 ... TD ... 31d ___________ 31d ... TD ... 31/1

. A . . . . 15 . . . 7 _____________ 7 . . . 15 . . . . A

CDI==box==<<<=== . . . . ===>>> CDI harness plug ===

31/1 -- Power ground
31d -- Signal ground [green coax shield] for trigger signal

15 -- +14 Volt power lead

7 -- Trigger signal from distributor magnetic pickup coil

TD -- Tachometer Drive signal

A -- +460 Volt pulse output to coil

patkeefe · 04-19-2005, 06:25 PM

Yeah Warren:
I went to 31/1 to ground with my ohmmeter to figure out the sticker is for the box. I'm going to new plug wires on, then test my fuel injectors. I had all of the prescribed voltages and resistances in the coil...does that rule out problems with the coax cable? Mine does have it, about six inches long, to the connector, then to the CDI unit. 31D to (chassis) ground is open.
Thanks for all of the literature and help. BTW, car starts fine, it just runs rough.
Pat

Early_S_Man · 04-20-2005, 10:19 AM

Pat,

That is normal for the green coax to show no continuity to ground ... it is only connected to the pickup coil in the distributor and not grounded to the distributor body.

Superman · 04-20-2005, 11:23 AM

Update. My Permatune CD box is useless because it has an intermittent failure problem. The fault seems like it's thermal-related since it dies after about 45 minutes of driving, but the CD box itself does not get hot. Barely warm at all.

At any rate, I posted a WTB thread on the parts forum. I'd like to buy a real Bosch CD box if possible. The new price for this part is obscene.

azasadny · azasadny's Garage

Superdude,
It seems like we are both having the same problem with our cars! My car starts and runs great, then dies after the car reaches about 180-190 degrees, then refuses to restart for at least 15 minutes, then starts up and repeats the sequence every few minutes. So far, troubleshooting hasn't helped and I'm waiting for a replacement Bosch CD unit from John Walker to arrive so I can swap the PermaTune unit out and see if that was the problem. Several folks on the used parts forum have Bosch units available in the $125-$150 range. I hope we both get this resolved because it's a pain (as you well know) to have your car die on the road, while you're driving, not to mention dangerous!

Superman · 04-20-2005, 11:54 AM

That does sound like the exact same problem I've been having.

I see Bosch units being offered occasionally, but I don't see one right now. Yet. I'd like to think you are correct, and that used Bosch units are out there for sale.

azasadny · azasadny's Garage

I just replaced my PermaTune (PermaDoom) unit with a used Bosch unit that John Walker kindly sent to me and I drove the car for an hour with no stalling! Looks like the 2 1/2 year old PermaDoom unit was faulty!

flipper · flipper's Garage

Hmmm..... my car was doing the same thing but it had an MSD unit in it. I replaced the MSD and it stopped for a day then started again. I then replaced the coil and it started again, for a little while, then shut itself off again. So now I have 2 MSD's and 2 coils. I dropped the motor to freshen things up before i figured it out, and it is depressing to think I will have to deal with this issue again in the next couple of weeks. This sucks!

patkeefe · 04-21-2005, 05:38 PM

New ignition wires (Clewetts) fixed my problems. The good thing about this was that I got to troubleshoot my ignition circuit (thanks to the help from everyone here), and found it to be ok.
Somewhat related, I have electronic industrial componenets at work, such as variable frequency drives, and they crap out when they get hot. I had to install A/C to the bigger ones to keep them from overheating. Why not try hanging an ice bag, or a piece of tubing from the fan housing, over near the Bosch/MSD/Peratune unit and see if that helps?
Pat