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Help. No spark

1K views 10 replies 2 participants last post by  laybackman 
#1 ·
So here it goes. '91 wrangler 4.0. I swaped out my injectors for ford 19# injectors. It started fine, but ran a bit rough. Took it out for a drive and it still ran a little rough, but I figured it was the the computer getting used to the new injectors, no leaks. Soon after, I dropped my gas tank because my skid was rotten and needed replacing. I replaced all of the soft fuel lines, vent hose and fuel filter at the same time. Now when I try to start the engine, it just cranks and won't turn over. There is plenty of fuel in the rail and hear the pump running. I've tried to let it sit, then turn the key to on multiple times to let pump fill the system. I am also getting fuel in the return line. During one of my attempts to start, I notice a small puff of smoke on the rear passenger side of the engine, but can't tell where it came from. I have tried to start it several times since, but it still just cranks. No further smoke. Battery is fully charged. Any help would be greatly appreciated.
Thanks my skid was rotten and needed replacing. I replaced all of the soft fuel lines, vent hose and fuel filter at the same time. Now when I try to start the engine, it just cranks and won't turn over. There is plenty of fuel in the rail and hear the pump running. I've tried to let it sit, then turn the key to on multiple times to let pump fill the system. I am also getting fuel in the return line. During one of my attempts to start, I notice a small puff of smoke on the rear passenger side of the engine, but can't tell where it came from. I have tried to start it several times since, but it still just cranks. No further smoke. Battery is fully charged. Any help would be greatly appreciated.
Thanks

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#4 ·
Are you getting spark to the coil wire on the distributer side end the wire?
If not the problem exists before the distributer.
 
#5 ·
Thanks so much for all the suggestions. Gonna pick up a spark tester tomorrow. Gonna check for spark at the plug first and work my way back from there. If there is spark at the plugs, then I'll pull the rail and make sure the injectors are firing. One or the other has to be bad. We'll see. I'll keep you posted. Still taking suggestions. Any chance it's the TPS?

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#6 ·
I do not think the TPS would prevent it from firing. It could be our ignition control module, (coil). That is in the area where you saw that puff of smoke.
 
#8 ·
Well it took me a while to get back into it, but there goes. I checked fuel pressure at the rail and it reads 40lbs. consistently while cranking. I believe this is the required pressure. Correct me if I'm wrong. I have also found that I have no spark, so this is where I'm stuck. There is none coming from the ignition coil. It appeared to be the original coil, so I changed it but still no fire. I also changed the crankcase position sensor, but still nothing. Battery is fine any help would be greatly appreciated.

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#9 ·
To update anyone fallowing this thread, 91 YJ 4.0. Swapped in 19# injectors. Ran a bit rough, but ran. Dropped tank to change skid. Replaced fuel filter. 40# pressure at the fuel rail. Good spark at the plugs. No fire. Just cranks and cranks. Replaced crankcase sensor and throttle sensor. No fire. Cranks and cranks. Good fuses and relays. Finally gave up and had AAA tow to The Jeep Shop in Chester Springs, PA. I'll let you all know what they find.

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#10 ·
To update, finally fixed. The number five injector was sticking OPEN. This totally flooded the engine. Fuel in the oil and everything. Oil and injector changed. Fired up. Compression back to normal after second oil change. What a PIA. Thanks all.

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#11 ·
That is an odd problem....but wait a minute! We are talking about Jeeps here aren't we!? Glad to hear you found the solution to your problem! :2thumbsup:
 
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