oneal916

Have 90 jeep Cherokee 17000 miles and running good up until a week ago drove it home one night every thing was good next day went to drive it. A lot of popping in the intake no power unless full throttle. once I do it levels out but still no power jerks a little and go to give throttle does the same thing I'm thinking fuel pump not sure !!! I'm stump change it out with a newer one out of a 92 ho to see if anything was different but no change .

67 GMC

Mine did this a lot before the fuel pump finally died all the way. If you have a fuel pressure gauge, check to see if you have pressure when you increase throttle. You might have it at idle but if it drops off when you increase throttle, could be starved for fuel. I'm thinking it could be bad fuel pump and/or plugged fuel filter.

cruiser54

YUP.

oneal916, have you performed any of my Tips on your 90 yet?

oneal916

Well I trouble shot a little and saw a leaking oring on a injector haven't been able to check fuel pressure yet going to just get a new pump fuel filter fuel regulator and orings and go buy a fuel pressure gauge and hopefully take care of my issue just have to wait till payday

cruiser54

Slow down a little bit here.

You may have a leaky injector itself.

They're notorious for that. Contact Programbo here on CF and get a set of 746 injectors from him.

In the meantime, borrow/rent a fuel pressure gauge from a parts store.

oneal916

Alright I look into it

oneal916

Alright so checked the fuel pressure got 20 psi @ idle had a injector leak fixed that new fuel filter and newer pump from a parts jeep . yes i now new fuel pump better than used .no leaks on the fuel rail pressure whlent back up to 30 psi at idle. replaced map sensor still having back fire and popping issue . could it be timing? what is the spec for tdc or before fire cause I'm thinking timming is the issue

DFlintstone

It really makes allot of sense to look at Cruisers stuff on grounds. You can chase your own tail all day and get nowhere if your sensors and stuff aren't grounding well.

Btw when I had identical symptoms on my 90, it turned out that some wires in that gang that come off the injector harness to the lower sensors were grounding. They were miss routed and contacting the heat shield. Your engine coolant temp, Knock, and 02 sensors are down there. No harm in taking a real good look at those wires.

cruiser54

Yup.

Jeepcrazy5722

Do the ground refreshing like others have said you are just chasing your tail until you know you have good grounds.

cruiser54

Yup...

oneal916

OK I'll start chasing grounds tomorrow after work, and wires and see where it goes ,keep you guys updated thanks for the help so far

DFlintstone

The reason it goes when you floor it is because Renix goes into "open loop" past 70-80% throttle. It ignores most of the sensors except the MAP and the CPS.

http://en.wikipedia.org/wiki/Yuppie "Not to be confused with http://en.wikipedia.org/wiki/Yippie." That's allot of Yup's Cruiser!

67 GMC

X2-Just had another one go on the weekend. At some point, I'm going to replace them all but have had 2 out of six go and leak on the body. I kept pulling them out and re-doing the O-rings until one of the forum guys told me the stock injectors develop leaks themselves. The good part is I can get that fuel rail off really fast like a pit-pro! It's amazing that I haven't had a fire with gas hitting the hot manifold!

cruiser54

746s from Programbo here on CF. You'll love them.