engine degrease - non start

911FL · 11-03-2007, 10:45 AM

Hope someone can help here. I just had a valve adjust and an oil pressuure sender (idiot light) replaced due to an oil leak. The tech used degreaser to clean up the topside and then sprayed a "protectant" (an oily smelly film) all over the engine compartment. I picked up the car yesterday afternoon and it ran great (he did say it wouldn't start at one point following the degreasing and messed with the ref sensor and speed sensors and then it fired up). Now it won't start. Cranks but won't fire. I cleaned inside the dist. cap and checked all the plug wires, even changed out the DME fuel relay. At a loss, and quite unhappy - beautiful day here in Florida and can't even enjoy it. Thanks for any help at all.

Hard-Deck · 11-03-2007, 12:45 PM

to that mechanic and make him fix it, he's responsible.

widgeon13 · 11-03-2007, 01:16 PM

+1, call him and see if he can come over as well instead of towing it to him.

Fishcop · Fishcop's Garage

It'll be a spark issue. It occassionally happens to me when I pressure wash the engine. I use compressed air to totally dry the distributor cap, leads (both ends) and spark plug ports.

Jeff Hail · 11-03-2007, 07:48 PM

Quote:

Originally Posted by 911FL

Hope someone can help here. I just had a valve adjust and an oil pressuure sender (idiot light) replaced due to an oil leak. The tech used degreaser to clean up the topside and then sprayed a "protectant" (an oily smelly film) all over the engine compartment. I picked up the car yesterday afternoon and it ran great (he did say it wouldn't start at one point following the degreasing and messed with the ref sensor and speed sensors and then it fired up). Now it won't start. Cranks but won't fire. I cleaned inside the dist. cap and checked all the plug wires, even changed out the DME fuel relay. At a loss, and quite unhappy - beautiful day here in Florida and can't even enjoy it. Thanks for any help at all.

Do you have spark?

Try above first (Quote:It'll be a spark issue. It occassionally happens to me when I pressure wash the engine. I use compressed air to totally dry the distributor cap, leads (both ends) and spark plug ports)

Old trick I learned a long time ago on Turbo motors with knock sensors.
Everytime we washed the motors warm they wouldnt start. For what ever reason the impulse signal from the dizzy got f'ed up.

Get or borrow a soldering iron (not the pencil type) like the heavy Wellers with the big coil in them. Plug it in, hold it next to the dizzy and pull the trigger. Dont touch the iron to the vehicle just close. The ignition needs to be on (run)The magnetic field generated by the iron coil would trip the impulse sender.

I thought this was nuts but it worked. I have seen Mercedes tech's use the same technique.

911FL · 11-03-2007, 08:21 PM

Well, I cleaned everyplace where there would be a loss in contact due to the wicking of the protectant. This included all spark plug wire connections and grounds as per the troubleshooting guide from this site. Still nada. Finally opened the coil plastic cover and cleaned, using alcohol, the connections there. Fired right up. Runs great and starts everytime. I really don't know why the tech felt he had to use that junk on the engine and will insist on not applying in the future. The shop is really good and the staff knowledgeable but this was a real snafu if you ask me.

Thanks to all that replied and Fishcop and jeff were right on with the electrical issue. At least I know the DME relay that has sat in the trunk works great and will keep the other now as a spare.

As an aside, the hesitation that I was experiencing for the the last three years is now gone. The culprit was most certainly the head temp sensor. The tech said the old one was loose and replaced it with one that came with the car (two wire upgrade). The car runs better than it has since I bought it!

911FL · 11-05-2007, 09:40 AM

Well, here we go again. Engine will not start. Could it be the Head Temp Sensor I had installed is defective? It came with the car but was still in the sealed plastic baggie. Would this cause the engine to not start at all? I loosened and cleaned the ground at cylinder #1 and jiggled the ref and speed sensor terminals (wrenches suggestion). He said he will come over this afternoon but in the meantime I'm just trying to troubleshoot as much as possible. Home alone so limited in checking spark, etc.

Any thoughts?

JeremyD · JeremyD's Garage

Check your transmission ground strap - (undo it, clean it, reinstall)

How old are your plug wires? How about distributor cap?