Cranks but No Spark and won't Start

[Vkgallo]

Hello, I'm fairly good at diagnosing auto issues but really am stumped with this one. Looking for any advice and would appreciate any feedback.:

I have owned a 1981 fuel injected 2000 for about 4 or 5 years. Car currently has about 67k miles. Engine is mostly stock set up with a custom cold air intake and a custom exhaust. Drove the car to a car show an hour in each direction one weekend. Few days later started the car up to wash and moved it to driveway. After the car was washed it would not start again. Eventually pushed car into garage. Noticed that gas was mixed into engine oil and because of that it was over filled. In the prior year or two the gas tank was restored, fuel lines, injectors, and fuel pump were replaced. Although they were new, I started there due to fuel in the engine. Fuel flowed fine and there appeared to be no blockages. I was able to manually blow into the return line from the engine compartment. Had minimal resistance but vaccumed line with a shop vac via a home made adapter just in case. No change in the minimal resistance. Figured was ok and changed the fuel pressure regulator just in case it was backing up somehow. Car would still not start. Checked ignition. No spark. I then believed the gas in the oil was probably due to me cranking the car way longer than needed. I also think I may have left the key in the on position accidentally when washing. My best guess is that since there was no spark the injectors was dumping gas into the engine every time I tried to start. I changed oil before moving to spark side of the diagnosis.

Before I get to my Spark diagnosis process, here is some history on the ignition side. In the last month prior to the problem the distributor magnetic pick up was replaced. The wires wore away on the prior one installed three years earler as it was rubbing inside the distributor. Did a better job on installing the new one this time to make sure wire was twisted so it would not rub again. Car ran fine after it was replaced a few months ago. Cap is also new this year. Here is what I did regarding current dilemma. I first swapped the ignition key with a working spare I had. No change. I then checked voltage to the coil. The postive lead worked but there appeared to be no ground connection as if I kept the positive on the coil from my volt meter and touched the ground pod with the negative side it read 12 volts but nothing if touching the negative on the coil. I removed the ground pod and cleaned all the connectors. Carefully squeezed the ends of the push on terminals so they would all be tight on the pod. No change. I did get a volt reading if I touched the negative part of the meter on the aluminum heat diffuser where the coil mounts (sorry dont know name) to but still no reading if direct to negative on the coil. I figured that the ground wire to the negative side of the coil may have cracked so I made a jumper wire from coil to ground. Still no spark. Swapped in a spare working coil and an ignition module in steps and still no spark. Used an ohm meter to test the magnetic pickup. read normal 750 ohms with no connectivity to distributor body as noted it should in the book. Also checked the coil. It was also in normal specks. A friend mentioned to make sure to check to see if the coil itself sparks as the problem may be inside the distributor. I checked ans still no spark right from coil output.

I'm really stumped. Any ideas? Has this happened to anyone before?

[RRoller123]

Do you mean that when you pulled the dipstick there was gasoline evident in with the oil? This is odd, as there is no obvious path for gas and oil to meet except past the piston rings, or past the intake valve seal. Both of these events need something to be quite wrong to occur.

Peripherally, It IS possible to flood the FI engine by repeated no-starting attempts, as the CSI will reset and start another ~7 second cycle each time. I have gotten so used to starting modern cars by just turning the key momentarily and letting go; letting the computer take over and complete the starting cycle, that I inadvertently did this one day with the Spider. It sputtered and died, I tried to restart a few times with no luck. Pulled the air tube and it was literally soaked with gasoline in there. Since then I stay conscious of the need to hold the starter on until it well fires, then give it a good accelerator pedal blip.

The CSI sprays a ton of fuel into the top of the plenum. It is surprising how much it puts in there, and it is no wonder the AAV also has to be working properly to get the air/fuel mixture right for cold start. The intake plenum and air tube all the way back to the throttle plate can become literally soaked with gasoline. When this happened to me, I vacuumed out the intake at the throttle plate (although there might have be a risk of explosion by pulling gasoline fumes through a wet vac, I had no such event) and then unplugged the CSI so no more fuel would be pumped in. It then sputtered to a start and ran smoothly as soon as it leaned itself out, then re-plugged the CSI.

But we need a little more info on the gas mixing with the oil to understand your specific problem, I think.

Pete

[Vkgallo]

Pete, thanks for the reply. I know my valve tappets have to be adjusted so that may be part of the issue as the gas may be leaking past the valves into the cylinders and going past the rings. With gas being so thin I'm not surprized they can slide past the rings when cold. I have not looked at my intake side but my exhaust side has gaps too small to measure as I cant get my smallest feeler gage under the cam and above the shim when lobe is pointing up. Tried removing shim but could not get it out. Was told by a friend that you have to be careful not to scratch anything as you can damage tappett. I recently came across a fiat factory laminated cheet sheet that says to use compressed air to help separate. I will try that after I get this started again. I can address the gas issue once I get spark back as I suspect the no spark is the main reason the engine is not starting. Any thoughts on that side of the issue?

[RRoller123]

That could be it for sure, no shim gap means valves are not closing. Fuel will just keep pouring into the cylinder while causing a no compression, no start condition and that needs to be addressed right away. I used a small neodymium magnet taped to a small screwdriver to lift the shims out. Rock back and forth and they pop right up then lift straight back and out. A small crook tool under the edge helps. Rotate the cups so that the small access gap along the side is facing towards you before you compress the spring with the valve tool.

Do NOT reuse shims when changing cams. Guy Croft is adamant about this, although an explanation isn't given in the workshop manual that I could find. I am guessing that the reason is that the cams are machined at a slight angle, to contact the shims slightly at edge and to force the shims to spin in the cups so they wear evenly, and are therefore matched to the cam. There is a reference somewhere to this, but I'll be damned if I can find it now. This is why they all show circular, concentric wear marks when you pull them out. Could also have something to do with unpolished, new surface holding an oil film better during break-in too. Not sure.

[Vkgallo]

Thanks for the input. Will try your suggestion when I do the shims after it get it to spark. Do you or anyone else out there have any thoughts on the no spark issue?-Vince

[spider2081]

I did get a volt reading if I touched the negative part of the meter on the aluminum heat diffuser where the coil mounts (sorry dont know name) to but still no reading if direct to negative on the coil.

The coil - or negative is not a permanent ground. You should be able to measure voltage with the meters negative lead on ground and the positive lead on the coils + and - terminals when the ignition switch is in the "start or run" positions. The cars ignition coil is just that a coil of wire so the voltage measured to a ground should be the same at both terminals of the coil. If the car was running you would measure a voltage less on the - terminal then on the plus terminal. The coils - terminal momentary connects to ground during the "flats" of the distributor cams rotation. This ground is broken or open during the "high points" on the distributors cam rotation. This opens the ground, causing the coil to produce the spark. Your car has an electronic ignition so the momentary ground and un-grounding is produced by the pick up and ignition control module. The coil should make a good mechanical connection to the heat sink and the heat sink should make a good mechanical connection to the car for maximum heat transfer.

[Vkgallo]

Thanks for responding. Here is an update. I turned out lights in garage and aparently it is sparking. Just did not see it initially. I removed the intake cover and the top of the inside of the intake manifold was filled with gas. I used a rag to soak it up. I also drained the oil and added fresh oil since it was overfilled by a quart. I suspect about a quart of gas was added to the crankcase oil from flowing down. I also noticed that raw gas was leaking out of the exhaust. So it was really flooded.

I checked to make sure the cold start valve was not leaking gas and it was not. (not surprised as it is new this year). after I let it air out, I put back together and disdconected the computer under the dash and the cold start injector electric connection. I tried to start car this way to attempt to burn whatever gas was in there. The car started right up and ran for a few seconds then stalled. I guess it was running on excess fuel in the cylinders. I reconnected the computer and tried to start and nothing. Then I plugged in the cold start injector and tried to start again and nothing. One other thing to note. On the long drive just before all this strated I noticed I was getting poor gas mileage. Perhaps it has been dumping in way too much fule but now it went overboard.

Wow this is really driving me crazy. Any thoughts? Does anyone know what happens when the computer goes bad? -Vince

[spider2081]

The burning rich could be the temperature sensor or its connector. It is the sensor located in the coolant "T"
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[lglade]

Ditto on the CTS idea. I had a broken wire at the connector on mine and experienced a horrible idle and raw fuel coming out the tail pipe before I diagnosed it. Replacing the connector and installing a fresh set of plugs resolved my problem.

[Vkgallo]

Thanks guys for your input. I have some followup questions and comments.

Regarding the coolant temp sensor. I had a spare one and no change when installed. The connector was replaced last year. While it is still possible the line is cracked, I think it is likely something else but I may revisit that idea.

Regarding the CTS comments by Iglade. I assume the CTS is the computer under passenger dash, correct? Where was the wire broken in your car. I looked at the connector and it looks OK. How did you determine that a wire was broken in the connector? -Vince

[lglade]

We may be talking in circles here, but CTS = Coolant Temperature Sensor which is located at the coolant tee, directly in front of the radiator at the center of a fuel injected engine.

The wires to the CTS on my car took a nasty/sharp 180 degree bend into the connector which was the location of my short. So when my car was running badly (shortly after a big service to the coolant system), I wiggled the wires and noticed an immediate change in the idle and how the car was running. So I disassembled the connector and installed a new one, including new Bosch terminals at the end of the wires. She's been purring along ever since.

But if you've replaced both the connector and the CTS, then maybe your problem is elsewhere.

Brad Artigue, in his L-Jetronic troubleshooting manual (available on his web site), describes a wiring/resistivity check which is performed from the computer side of the harness. You might try that to verify you don't have a short somewhere in the CTS leg of your harness using his methods. Your're not supposed to do a continuity check from the sensor side because the current applied by the tester could short out the computer, so you must do all testing from the computer side.

In your shoes, I'd try to focus on just those systems that you sprayed during the car wash. Between the moisture and mechanical impact of the spray, something changed on your car. Where did the blast of water go? If the car ran okay before the car wash, but no longer, then something you did is causing all of this grief, right? If you can get your car to run at all, then jiggle wires, hoses, modules looking for that change in rpm that suggests that this is the system that was affected by those kinds of influences.

[Vkgallo]

Thank you. I did check the connection to the CTS and it was reading voltage. Good idea on the testing wires from the computer side. Will try that next. Thanks-Vince

[Vkgallo]

Hello all, wanted to give you an update. With the help of Andy, the head mechanic at Vick's Auto, we dermined that the issue was computer related. The computer is stuck at full throddle output which is why so much gas is being injected to the engine that it drips out of exhaust and goes into oil. Here is what we did to determine that after ruling out other items out as most of the FI system is relatively new.

1. I used Brad Artigue's L-Jetronic troubleshooting manual found online and tested sensors and such from the harness with ECU removed using ohn meter. Found no problems as all readings were normal.

2. With computer still disconnected, I used an ohm meter to make sure there is no short in the wiring. I tested each of the two wires from one of the injectors. made sure there was no conectivity between the two leads and each lead to ground. If there was there was a short. Luckally for me the wires are good.

3. reconnected CPU and used an auto stethascope to listen at the injector itself for clicks with each rotation of the engine with starter cranking. There were no clicks meaning that the injector was not firing in conjunction with cylinder. It is stuck open via signal from the computer = short in CPU.

Lastly wanted to pint out a comment he said. Andy said that while ECU problems were rare in the past he is seeing more and more of them lately. Mainly because the computers are 30-35 years old now. After gettig off the phone I thought to my self. How many computers and other complex electronics work well after 35 years of heat and abuse? While I could have purchased a used computer, I chose to have mine rebuilt for $375. I think it is a better idea as who knows how long a used one that works will remain functioning given age. Thanks-Vince

[RRoller123]

Excellent resolution! Thanks for sharing the result.

[Vkgallo]

Here is an update. Stiil waiting for the CPU to be rebuilt at Vicks. However, they did tell me that the CPU has an odor of something electrically burnt which is more proof that it is most likely the computer. Expect to have the rebuilt CPU in time for next weekend. Will keep you posted.