Update on 308 belt change

Hello

We were changing the belts. When we got in, we noticed that the belt on the front cams was still in place but torn; All timing marks lined up.

We therefore thought that the sluggish perfomance suddenly occured was probably not the timing belts. It was probably good fortune that we looked at the belts because this one was going to go anytime.

We changed the belts and the car still seems sluggish. We are having trouble determining if it is firing on all cylinders.

We removed the spark plug wires to check for spark. The front bank has none, and now the car won't start at all.

Last year, the car would stall and not start. We traced that problem back to the electric fuel pump fuse. Short. We placed an in line fuse and it has run fine since, up until now.

Because me noticing the tear in the timing belt was most likely conicidence and not directly related to what I though was a "miss" or "slip". We are now going to pull the spark plugs and try to determine if we have a problem with the wiring or coils. We are considering replacing the fuel filter and possibly the electric fuel pump.
Any suggestions would be greatly appreciated.
Thanks. Brent. p.s. The back cam belt looked new, the front was the one that was torn. We think there is a possibility that those who changed the blets in 2004 only changed the easy belt. That's what it looks like.
Thanks.

 

Brent,do you know when the last time the belts were changed,just wondering how miles or years you got out of them? and have you checked your coils,you might hear from my machanic,and he'll chime in I'm sure you'll get some advice what it'll might be

 

The belts were changed in 2004 about 2000 miles ago.

We have been fooling around with the car.
It seems to run on the front bank, but the rear bank is not firing. There is no spark on the rear bank.
So we think we have isolated the problem but are not sure how to proceed.

We want to investigate the electronic ignition module. We are having some trouble locating them.
We are also trying to follow the wiring diagram for fuses. Are there separate fuses for each module?

Any help would be appreciated.

 

I got a response indicating the coils may be the problem. I am going to look up threads on coils.
Brent.

 

you mean I might be right? goosh thats a first .........lol

 

In my 308 [1981] they are located in the trunk, under an access panel on the drivers side. Check your grounds, swap the modules and see if it moves to that bank. Check your coil connections, rotor and cap, fuel injectors, etc.

 

First verify there is not output from the coil--a clamp-on timing light works good for this test.
If there is no spark, look at the low voltage side.
The low-voltage plugs for the modules, etc are problematic especially if they have been bumped.
The high voltage circuit has a lot of voltage so be very careful touching that part of the circuit with the ignition on.
I would check the connections on the coils and the module on top of the coils by wiggling them around while the car is running.

Check for power to the coil with a test light then trace up and down in the circuit.
With a test light and by swapping the coils & modules you should be able to hone-in on the culprit.

Do not run it too long with a bank-out because the raw fuel is just being pumped into the system.

Keep us posted.

Mark
Mark

 

Hello
After looking everywhere I finally found the Electronic ignition modules.
I switched them and the problem followed the switch. Initially the rear bank had no spark and the car was running on the front. When I made the switch, the opposite occured.
I was trying a few combinations then the car flooded. Have not pulled the spark plugs yet.

After reviewing the previous owners maintenance records I noticed coild, distributors and wires were changed in 2002.

From what I have read on the threads, it appears that the digiplex is the problem. I have been looking at prices and some are very high.

Am I correct in assuming that the digiplex is the problem?
Where should I get a replacement if I need a new one?
Should I replace both or just the affected one?

Any advice would be great. Thanks again. Brent.

 

After discovering that the digiplex was at fault. I removed the one that I thought was the problem. Opened it up to look for loose wires....or something odd. Could not see anything. Blasted it with compressed air. Did the same for the connectors and put it back in the car to double check that it was the digiplex....before spending money to replace it.
After fooling around with things for a while, switching, etc. , I finally connected them both and the car is firing on all cylinders as far as I can tell. I now have spark to both banks and it sounds a whole lot better.
Cannot test drive today. It's raining and she doesn't like to get wet. But it feels like her power has returned.

Is this problem solved, or intermittent problem waiting to reccur?
Is there a way to test the digiplex?

Thanks Brent "I'm Happy for now" Pilon.

 

Brent:

Glad you got it running again!
Are you having trouble with the digiplex (under the "trunk" carpet) or the ignition modules (on top of the coils) ?

The modules are not very expensive and I think when you switched them and the bank fired it proved that the modules are good and that the module plug or something like that is bad. On my car the plug / harness going to the coils is sensitive. If it is moved around a bank will cut-out, but if it runs and I leave it alone there will be no trouble with it.

I think there should be a smear of dielectric grease between the module and the coil--helps with cooling.

Glad you received some help here.

Mark

 

I switched the digiplex in the trunk and that's what made the difference.
I took the digiplex appart and sprayed it with compressed air; then sprayed the connectors.

As far as the modules on top of the coils, I have to be honest and say, I'm not really sure what I'm looking for;
I read threads on 328's having modules above the coils but I did not know the 308's had then as well.
Mine just has a red 3/4'' bar, bent at 90'.

I will have a closer look at the coils. I am assuming they are fine because it is now running well, but I would like to learn more about the modules.
Thanks as always. Brent.

 

Brent,

The grounding on the digiplex units is notoriously bad. You might want to add a separate ground strap for the units to assure they are properly grounded. As I said in another thread recently, I re-learned an old lesson taught to me many, many years ago -- 99% of all electrical problems are the result of faulty grounds.

 

I second that!

"If you can't fix it with a hammer, you've got an electrical problem" ;-P

 

Odds are you encountered the infamous Digiplex ground problem. Do a search for 'digiplex' and 'ground' there's a thread with pictures showing how & where to install a braided ground strap to ensure it won't recurr.

The other alternative is that you had connector tarnish. Suggest coating the connectors with dielectric grease, it will keep O2 & humidity away from the points where they make contact.

 

Thanks for the info
Car is still running great, but I will do the things mentioned above to make sure it stays that way.
Thanks as always;
Brent

 

I’ve been unable to find any such photos. Does anyone remember the particulars?