Paul91

Changed plugs and wires, resealed injectors, then no start. Car was running great before the minor maintenance was performed.

Put a multimeter on the harness plugs (all unplugged, key in on position) and I'm getting no reading across the board. I'm guessing a short somewhere. I have fuel and spark confirmed. 2 DME relays and I've swapped with no luck.

I did notice that the ref/speed sensors were loose, so I torqued to spec and still no start. I have tach bounce...slight, but it's there.

How can I diagnose a short for the harness? Also, if one of the harness plugs has a zero voltage reading, would that cause the other 3 to read 0 as well?

Thanks

refresh951

Sorry you are having trouble. Since you say spark and fuel confirmed, make sure the plug wires are correct on the distributor.

Not sure I am following, are you putting the multimeter on the injector harness? How did you confirm spark at each cylinder.

Paul91

I confirmed spark with a plug tester light that goes between the plug and the wire. Thank you for the diagram from Clark's. The wires are in the correct order.

Ohms were checked using multimeter probes connected to the 2 tabs of the injectors. Attempted voltage check with same device, touching the connectors on the wiring harness. As mentioned, I also used a NOID light to test the harness connectors.


I'm wondering if I cracked the internals of the harness wiring somehow. Will peel the rubber back to see tomorrow.

refresh951

If you confirmed spark on each cylinder then the DME is firing which means the ref and speed sensors are working. You can confirm the injectors by using a multimeter back to the DME connector. Pretty common for the original injectors harness to short at the injector connector.

Paul91

Thank you very much. Would this require a new harness, or some soldering of the DME unit itself to repair?

I suppose I should search the DIY on Clark's for this procedure.

Thanks again.

refresh951

Not at all. You can pull the DME connector off the DME and then do a continuity test between the DME connector pins and the injector harness pins for continuity.

This may help:

http://www.lindseyracing.com/LR/Parts/CHIPCHANGE.html

Rich Sandor

Just an FYI.. a common problem with the injector harness is broken wiring inside the wiring harness where it's bent or crimped around the fuel rail. Because it's cracked/broken, it result in intermittent connection.. testing with a multimeter might show a good connection - until it's jiggled or vibrating.

Ive attached a photo of what my injector harness butt looked like when I cut it open. Note the wiring was severed before I cut the butt open.

Paul91

Thanks Rich. I'm going to cut/pull back the boots in about 20 minutes. I currently am not getting any reading at all out if the multimeter on any of the harness plugs.

Paul91

Rich- I owe you a cold one, sir

Paul91

Update: Installed the LR injector harness with knock sensor plug. Car fired right away and then started making squealing (belt-like) noises. I shut it down. Now it won't start again...just cranks but won't turn over. I'm about looked and felt some of the belts. Everything is on fine. Any other ideas?

Black51

Start with the basics again. Are you getting tach bounce? Spark and fuel? Did you accidentally wiggle some other questionable wiring harness, or unplug something while installing the new injector harness?

Paul91

I am getting fuel and spark. I have tach bounce, but the needle is barely moving up and down. Should it be moving more? I installed the LR fuel injector Harness, and discover a problem that the #4 injector isn't getting a reading. This is the email that I sent to Lindsey racing:

After following your install directions, my car still won't start. I tested the harness connectors with a multimeter, and connectors 4,3, and 2 are all showing a solid 19 Ohm reading. However, plug #1 is dead and showing no Ohm reading. Since the DME #15 pin/wire controls plugs/cylinders 1&2, this leads me to believe that the # 1 plug is defective (considering #2 is strong).

Chris White

it would still fire and run of three cylinders...so it sounds like you may have two things happening concurrently. The squealing may have just been the alt belt - since you have been doing a lot of cranking the battery was probably low and once it started it put a heavy load on the alt to recharge the battery.
Try starting it with #1 injector disconnected. If the load is too great the DME will not fire the injectors.

67King

How do you know it is getting fuel? I'd make sure you are getting spark first (i.e. pull a plug and see if it fires when you try to crank). If you are, pull a plug, pour a little fuel into a cylinder, then reinstall plug (and wire), and see if it fires. Won't "run," but if it fires by putting fuel in that way, then you have an issue with fueling. If it does not, then ignition is your likely problem.

Paul91

Thanks for the replies/ideas. I have a new fuel gauge installed on the rail that's reading 41 psi during and after cranking attempts. That being said, I suppose I should pull the rail off with the injectors installed and crank to see if the injectors are spraying. I had originally removed the injectors to reseal them since I noticed one was leaking on the block.

Pouring fuel into the cylinders is a good idea. Any suggestion as to how much? I'm a novice mechanic at best and have learned a lot from RL. Thank you for your patience and overall input.