StuK

Since I gave my '88 a "tune down" Sunday and it won't start now with a new cap, rotor, plugs and wires, I have a question about the connections to the coil. I tried a new battery last night, replaced the pickup in the distributor so, rule those out.

The connections to the coil you have the large connector in the back next to the distributor body and then a white wire single and a red wire single which each connect to white and red leads coming off of the coil.

The white lead out of the coil is labled "tach" and the red is labled "battery". I did not mark these two connections as i figured there is no way I will forget these two connections... maybe I did?

The white lead from the coil I connected to the white wire which seems to head towards the firewall so, I assumed that was the tach wire and white out of coil to white wire outside of the distributor right? The heavier red wire would be a hot lead to the battery right?

I am just wondering if someone could verify for me if the red wire connects closer to the firewall and the white connects to the post closest to the engine intake?

Trying to nail down what happened here as I did not do anything I consider extreme in changing the cap and rotor yet I lost engine ignition.

Thanks in advance for any suggestions and verification of my wire positioning!

Stu

Bullseye54

The tach/white wire goes on the left/front connection & the batt/red on the rear.Make sure the coil was installed right,the contact w/spring goes in 1st with the rubber gasket next to coil & grounds connected right.................Bob

StuK

Cool, thanks for the verification Bob. That is how I put it back.

I will clean the contacts tonight and verify coil contacts are good and the connections. The contact and spring were installed in proper position. Definitely making me crazy!

Stu

leesvet

Yep...

I'd go back and disassemble and repeat the process to find whatever was done wrong or missed.

NOTE:

its VERY easy to pinch ign module wire under the cap edge. Get those wires pulled out and away from everything. If one is slightly skinned, its grounding and won;t allow a spark.
Check that dist body bulkhead seal too...the wires can ground there as well.

Make sure the ICM is seated in a good bed of silicone grease....very important. Don;t worry about it being everywhere. It will but it does not hurt. Better to have the heat-sink effect than not.

Tried a spark tester yet? cheap tool that shows you real quick if the sparks there and if its hot enough to build a fire. May want to check that BATT wire to see if it IS hot. That comes from a fusable link under the battery IIRC and can blow by casual contact during the tune up process.

Also make sure the cap is fully seated...easy thing to mess up, really.

StuK

Negative on the spark tester. Just did the lay a plug on top of the engine and watch the spark test. It was hot first rev and got progressively less intense with every cycle.

In replacing the ICM last night, both sides of the connectors were brittle and in rough shape (The left side standing from drivers side of car looking down) and broke up partially. I thought I got it back together enough to work but, if there is a ground fault possibility internally, I can see an issue there.

Do you guys know of a chain parts house like NAPA, the Zone or O'Reillys that carries internal distributor wiring? Definitely wouldn'y hurt to replace the condenser side which exits to the coil. Would hate to have to buy a distributor just to get the part out of it to install on this distributor but, it's my transportation to work and I really need to fix this issue asap.

If there is a fusable link, that's possible too. Would that allow a verifiable spark though if it was blown? The grounding possibility seems more likely?

leesvet

ALL those dist parts are available at most any parts store. Just avoid the cheapo ignition module...they're generic chinese junk. Try to stay with Delco if at all possible,. if thats not an option take what you can get, just get the best you can ! The ing system is delicate.

You can get the ign module tested at the [parts store too. If you have O'Reillys auto parts in your area you can look up any part for the car on their website...same for Auto-Zone and Peep-Boys. That way you can see prices and make decisions and walk in with a part number so the counter guy has a chance of finding what you need..

All of the "internal" wiring is attached to somethings thats got a part number. Module, base pick-up etc.. Once the wires are damaged the part is pretty much toast.

StuK

Looks like from the NAPA site what I need to get to replace everything that has possibly been cooked is:
1. Distributor Capacitor & terminal block
2. Stator
3. Pickup Assy

That appears to be everything internally with a harness. Sound resonable?

Thanks fellas!
Stu

engle1147

The heavy red goes nearest the firewall. The connectors are actually "keyed" so they should only go back easily if they are in the correct positions.

Another thing that people often seem to forget to do is transfer over the ground strap (secondary ground bar) from the "old" cap to the "new: cap.
Looks like this:http://shop.advanceautoparts.com/web...RPTUNEAMS_____

StuK

Thanks Engle. Yep! That's how she was put back together. Appreciate the visual...

StuK

Alright... I am not feeling as foolish as I was earlier. A buddy from work came to assist me after work tonight and we went through double checking firing order, plug gap, thought the anti-sieze on the plugs may have been preventing a good ground so we cleaned them off.

We are getting gas and we checked the spark by letting the plug terminal for cylinder #1 arc to the coil which was .5 inches away and the spark was orange rather than a white or blue. My buddy called another of his buddies who explained that test.

He worked for a dealership for ten years in the shop but, he was 10 years old when this car was made in '88 and has no L98 OBD1 exp. Competent but, not on this old stuff.

Anyway, apparently we have spark but it's a weak spark. Engine does not kick at all on it's own.

I just ordered the capacitor harness which goes from the ICM to the coil and I will pick that up tomorrow... There is a data harness coming out of the opposite side of the distributor and plugs into the opposite side of the ICM. Both harnesses are in rough shape.

I am thinking that data harness might be an issue as well as the car had the original ignition wires at 24 yo and 148K miles and they needed some back and forth working to pull through from behind the distributor. That process may have damaged the data harness as they were in contact with each other I am thinking.

Anything in those two harnesses that could be responsible for a spark so weak the engine wouldn't kick?

Thanks,
(long winded) Stu

engle1147

Hey Stu - are you using the same stock hei coil or did you change it out for something else when you did the new cap, rotor, plugs and wires?

StuK

Negative. I put a new one on last night though trying it to see if it made a difference. Same result. One thing I think could have happened was during the removal of the "original" 1988 spark plug wires was removing the two that crossed behind the distributor may have disrupted the harness which goes from the dist to the ECM in the firewall. One plug was difficult to get through and I ended up cutting it to pull it out each side without yanking the cap thru taking whatever was behind there with it. The initial pulling and twisting may have messed up that rear harness which is a discontinued part. I found a new terminal block I will install when I get home tonight. I am getting spark and fuel but the spark is weak. Too weak to fire the engine.

The only other idea I have is if the spark plug wire resistance is too high.

engle1147

Makes me think you've got poor grounding to the coil - which is why I asked and mentioned all the things I did in the above posts.

I'm asking because you never really mentioned if you did remember to reuse the ground strap/bar the first time you put it all back together. What coil did you with and does it require the use of the "ground strap/bar" I linked in on post 8?

StuK

I did transfer the coil ground strap. I actually slightly bent up a corner under the coil when I put that new one in last night to make sure they good good contact just in case.

engle1147

The rest of the wiring (internal - harnesses - ICM - pickup) doesn't have anything to do with a "weak" spark.

Coil/rotor related issue(s), low voltage (takes over ~10VDC to fire off a HEI system properly), grounding issue(s), improper parts, installation and or wiring could be the issue.

What HEI coil are you using exactly?
What plug wires did/do you use?

Double Check Check list:
Coil is getting a minimum of 12 volts (+)
Coil is grounded (-) properly all the way back to the battery
The installation of the "button", spring & rubber insulator that contacts the rotor is correct and secure - (all stuff under the coil)
Rotor is installed properly
Cap is totally seated and tight.

StuK

Question: What would the engine do if the harness from the distributor to the ECM was disconnected? I replaced the Terminal Block (with the capacitor) tonight. No change.

I put the stock coil back in and the old plug wires just in case it would help. No change.

I am curious about that rear harness. I am assuming the engine wouldn't run if it was damaged right? The ECM controls the timing and what else having to do with spark?

If all else fails. Is there an aftermarket distributor that will work in an '88 without the guidance of the ECM? If so, which brand/model and what will it affect as far as normal operation?

StuK

Sorry i didn't address your questions Engle.

Wires NAPA Belden Max Premium p/n 700386
plugs AC Delco FR5LS
original coil back in
We were getting 12v from the hot we even ran a wire direct from the post to the coil to make sure it was clean and hot.

Stu

StuK

Where exactly is this and what does it look like? IIRC term? I am not familiar with the acronym. I would like to check this... is it under the battery? Does something pop open to expose it?

StuK

It really hurts my wallet but, I ordered this part:
http://www.ecklerscorvette.com/corve...1984-1991.html

It's the part I suspect was damaged in removing the original plug wires and is just about the only ignition part I haven't switched out yet. Discontinued from Chevy of course.

I did check the fusable links and replaced on even though it wasn't burnt. Just seemed like it was in bad shape physically so... Friday when the $5 to mfg part I paid $130 for arrives we'll know if that's the offending component.

Thanks fellas for all of your knowledge, experience and suggestions. Cool thing about this experience is I pretty much learned a ton about TPI ignition!

Cliff Harris

The BATT connector is the one with the pink (not red) wire. It should have 12 volts on it when the key is on.

IIRC = If I Recall Correctly.

The four wire cable goes to/from the ECM and controls the spark advance. You can bypass the ECM connection by disconnecting the EST bypass connector. It is a single wire connector with a tan wire with black stripe, located next to the brake booster (below the windshield wiper motor). With this connector open the ECM spark advance is not present and your spark advance will be whatever the mechanical position of the distributor is set to. It should be 6 degrees of advance. The key item here is that the ECM is out of the equation with this connector open.