Fuel at injector but not at spark plugs

jpjeep26uk

jpjeep26uk

YJ Enthusiast
Joined
Nov 12, 2022
Messages
253
Location
UK
Hi all, I'm on the mend and back to figuring out my Jeep.
It's been in the shop as it won't start and they can't make it start.

I put a new ECU and new injector in (before getting it towed) and it started but ran an drove something terrible. Black smoke, next to no guts/ power, coughing spluttering, stalling unless you kept the revs up. Nightmare.
I limped home and it stalled and won't start.

It cranks really well and there is fuel at the injector but it doesn't seem to get to the plugs to actually start the vehicle. I put a couple gallons in the tank to provide fuel and checked the flow and it seems unhindered through the fuel filter up to the throttle body.

The fuel appears to be injecting but it sits in the bottom of the throttle body and then it ignites in a single whumpf! And that's it.

There is a healthy spark to all four plugs. I've replaced every single sensor in the bay and done TDC.

Any initial ideas folks?
There are a nice shop, good people, but this is simply not your average car here in the UK and I'm hoping you folks can maybe offer some things to check out?? Thanks all.
 
could the black smoke be a plug cat. have you tried just putting fuel down the throttle to see if it runs.
 
Would a 1991 cat fit a 1989 YJ? Over here I can find lots of 1991 -1996 but not a single 1989 but they look identical.
 
it you can get on quadratel net, it states a direct fix for 87-92 on 2.5l. if you dont already have there parts book they will be glad to sent you one. good luck and safe driving
 
If you really think the black smoke is from a plugged cat, don’t put on a new cat to find out. Why not just cut the exhaust prior to the cat which you would have to do anyway and fire it. up and see if it’s still smokes. Did you happen to clean out your throttle body?
 
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just a follow-up, i went back to your posts 2022 and you was having black smoke problem at the time, a intake bolt seem to be problem, did you get that repaired?later you needed to adjust your IAC, how did that turn out? it seems that you still having the same problem. have you test the fuel with a fuel pressure gauge?are you using champion plug. you mention engine difference in UK, those engines are the same as USA. Chris, the admin. of yj forum has a PDF or orgin. manual of your wrangler or a download you can get. is it possible that you need a new intake gasket? if you get the manual, you could share it with the shop at your using. good luck.
 
dieselearl said:
have not hear back from you, what is the status of vehicle at this time? thanks
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Hi! Sorry for the radio silence, been from pillar to post on the health issue and other personal issues.

Hope all is good with you.

So, about 5 or 6 weeks ago a local garage offered to take the Jeep in and run a full physical analysis on it and get it past its MOT.

Brilliant I thought, as I'm not well enough to work on it right now and I lost my licence due to the illness.

They didn't touch it.

So it's now at a car dealer friend of mine (who sprayed it up in 2022 as a Jurassic Jeep) and he's all over it.

He got it running and has asked me to buy a fuel pressure regulator as it's flooding the engine each time it's fired up.

So this morning I'm on the hunt for a FPR to se if that does the trick.
I'll post back with results!
 
dieselearl said:
just a follow-up, i went back to your posts 2022 and you was having black smoke problem at the time, a intake bolt seem to be problem, did you get that repaired?later you needed to adjust your IAC, how did that turn out? it seems that you still having the same problem. have you test the fuel with a fuel pressure gauge?are you using champion plug. you mention engine difference in UK, those engines are the same as USA. Chris, the admin. of yj forum has a PDF or orgin. manual of your wrangler or a download you can get. is it possible that you need a new intake gasket? if you get the manual, you could share it with the shop at your using. good luck.
Click to expand...
Hi, Yup, got the bolts all tightened. One had actually fallen out! Which was the culprit on the backfire.

I did buy an intake gasket but never got round to installing it as I was in my mechanics for dummies stage and it was too daunting haha.

I replaced the IAC at the same time and she worked fine again so I think it might have been a combination of the bolts and the IAC. She ran perfectly after that.

I'm thinking the guy who has it and asked me to buy a Fuel Pressure Regulator has done the FP test and found a wacky variance or it's just plain busted.
 
Just noticed you're in MO.
I strayed into MO in 2017 by accident haha. I was on a solo road trip and staying in Belle Fourch in SD and drove north to find the old US highway to visit the Centre of the US. Took a wrong left and ended up about 50 miles into MO before I stopped and a local told I was in the wrong State 😄
 
redbullet said:
If you really think the black smoke is from a plugged cat, don’t put on a new cat to find out. Why not just cut the exhaust prior to the cat which you would have to do anyway and fire it. up and see if it’s still smokes. Did you happen to clean out your throttle body?
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Hi Red, sorry, been a tad busy, I didn't get around to testing the exhaust or clean out the TB as I had it towed 6 weeks ago as a local garage told me they have a look and fix it.
They didn't do either as far as I know so I haven't seen it since late May.
It's with a friend of mine who deals with top end sport cars as his mechanic is old stool and has already spotted stuff in just a day of having it.... they think it's the fuel pressure regulator.
That's not an easy thing to source here in the UK so.im scouring the.internet as we speak!
 
redbullet said:
Another thought. Have you ever changed the fuel pressure regulator?
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That's mighty coincidental as my guy literally texted late last night and asked me to buy a new FPR!
I'll post an update as if it's that then it might help someone else with my chain of issues.
 
Is this the fuel pressure regulator?? (2.5l 4cyl- 1989)
20240709_081803.jpg
 
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