88 Turbocoupe no crank

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88 Turbocoupe no crank

May 14, 2020, 01:01:57 PM

Having an issue where the car gets power, but will not crank. Suspecting the starter as bridging the posts on the solenoid does not crank the vehicle. Battery tested okay (jump box also made no difference), car behaves as expected when clutch is both engaged and disengaged, as in it will not attempt to crank with the clutch out, but WILL attempt with the clutch depressed. I'm getting ~8 volts at the battery when it attempts to crank. I can hear the fuel pump priming, and the hydraulic pump working when the car gets power. Cluster lights work and dim when attempting to start (and do not when clutch is out). Again, I suspect the starter, but wanted to get y'alls opinion.

Re: 88 Turbocoupe no crank

Reply #1 – May 14, 2020, 01:15:07 PM

I think the rule of thumb is 9-10 volts across the battery when cranking. Don't quote me on that.

Any possibility you could try jump starting it from another car running? I've had my jumper box not put enough juice out before and before trying to get that starter out it might be worth a try. That starter is not in a fun reachable place.

Re: 88 Turbocoupe no crank

Reply #2 – May 14, 2020, 01:45:14 PM

Quote from: Mikey97D – on May 14, 2020, 01:15:07 PM

I think the rule of thumb is 9-10 volts across the battery when cranking. Don't quote me on that.

Any possibility you could try jump starting it from another car running? I've had my jumper box not put enough juice out before and before trying to get that starter out it might be worth a try. That starter is not in a fun reachable place.

Jumper was at 12.4 volts and 92% charge. It's been a real workhorse and was regularly used for the escalade's 6.0. I may be able to jump it with another car, but not immediately.

Re: 88 Turbocoupe no crank

Reply #3 – May 14, 2020, 03:26:50 PM

Sounds like the starter has taken a dump and is really pulling the battery down when trying to crank.

Re: 88 Turbocoupe no crank

Reply #4 – May 15, 2020, 04:16:42 PM

UPDATE: After staring at the EVTM and the Chilton manual, playing with wiring and trying to make sense of everything, I finally broke down and pulled the starter. Took it to the local PepBoys to have it tested annnnnnnnnnnnnnd its good. At least on their test bench. So my options are again limited to wiring.

On that note, I have some questions. If someone can take a pic of their starter solenoid (relay) and how the wires on it are configured (88 TC) that would be a huge help. Also, I have three connectors on the driver's side that seem no to have a home. I've scoured the EVTM and the manual and these wires just aren't in the diagrams.

Connector 1: 2 PIN (Orange/Light Green and Black and Yellow) Long wire originating from main harness along firewall, D/S
Connector 2: 1 PIN (Red/White or White/Red) Short Wire in same bundle as brake master cylinder
Connector 3: 1 PIN (Black/White) Short wire just off washer fluid reservoir (seems to be related to washer fluid level sensor but unable to find unused male single pin in the vicinity)

I would like to believe one of these is my problem, but I don't think they are. Regardless, if anyone knows where they go, I'd be grateful. Besides these, are there any common ground wires I should be checking for breaks/shorts?

I will say the car started just before I fixed the ignition switch issue I was having for which I pulled the driver's seat out and removed all the excess stereo wiring. There was a pretty hefty 4-6g wire for what I assume was a sub/amp that I pulled out through the firewall and I think that may have messed with something but there was no evidence of damage to the harness when I pulled it to check for shorts.

Re: 88 Turbocoupe no crank

Reply #5 – May 15, 2020, 05:13:22 PM

When you bridged the starter solenoid did it make sparks to indicate the motor is drawing current?
If so: it sounds like the engine is seized up. Pull the plugs and see if you can turn it over.

Re: 88 Turbocoupe no crank

Reply #6 – May 15, 2020, 06:30:21 PM

I turned the motor by hand, and yes, the solenoid does spark when bridged, but does not run the starter.

Re: 88 Turbocoupe no crank

Reply #7 – May 17, 2020, 10:11:48 AM

So in backtracking everything I've done so far regarding electrical, I've pulled the harness again to see if there were any shorts. I found nothing other than some spots near fusible links with exposed wiring which I assume is fairly normal, but I've taped them all up anyways. I also pulled the ignition switch again to see if that may have had something to do with the issue and found I may have installed it improperly. Fixed that little mishap and tried starting it again using the jump box (fully charged) with no real change. I can now hear the heavy clunk of the starter attempting to engage, but not the tell tale whirring noise of it actually trying to spin up. The jump box is still reporting a drop to ~7.5v when attempting to start. I decided to see what the values were for just the battery in the various ignition switch positions as follows:

Jump Box: 1300CCA 13.0v
Battery: 8.0v
IGN off (locked): 8.0v
ACC rear: 6.5v
ACC front: 8.0v
RUN: 0v
START: 0v

With this info, I'm thinking I may have fried a module, burned up a fusible link, or may still have a bad ground somewhere that I've been unable to find. Please also see previous post about random connectors that have no home. Thoughts?

Re: 88 Turbocoupe no crank

Reply #8 – May 17, 2020, 01:05:51 PM

1. Disconnect the negative battery cable from the battery.
Does the battery still measure 8v across the batt terminals?
2. If so, hook the negative cable of your jump box to the disconnected battery cable. Hook the positive jump box to the positive battery. This will take the battery out of the picture. Try to crank it.

Re: 88 Turbocoupe no crank

Reply #9 – May 17, 2020, 02:17:25 PM

**FIXED**

So after doing a little more research here on the forums, I saw a recurring trend with the ignition switches going bad. Also, with plenty of fords in the family and in my friends group, everyone always seems to have a spare starter solenoid on hand. Since I also knew the battery was likely a problem, I decided to make a parts run down to PepBoys and pick up the trifecta. While I was there I picked up a new negative terminal since I suspected it wasnt clamping properly.

WITH YOUR POWERS COMBINED, I AM A RUNNING THUNDERBIRD!!!!!

Thanks all who helped me pull my head out of my behind on this. You guys are awesome.

((Would also like to note that the battery was a month old, the solenoid was two months old and the ignition switch was OEM and looked like it was starting to come apart. When I replaced the -term, i cut the wire back to clean copper. Was so convinced that the problem couldn't possibly be something I so recently replaced that I neglected to check the common issues.))