I need some help PLEASE. New cap and rotor, new fuel filter, new vacuum advance, cleaned MAF, cleaned stepper, timed and checked for vacuum leaks. Idles very smooth and will rev with no load. As soon as I attempt to accelerate under load it bogs and backfires and dies if I don't take my foot out of it. Before I cleaned the MAF it died as soon as I unplugged it. Now that its clean it runs the same with the MAF plugged in or unplugged. I am new to Rovers and fuel injection (with all its sensors) I have done everything I can think of (that I would have done to a CJ5). Thanks in advance for the help.

 

I forgot to mention: I checked the screen under the passengers seat for codes, there are none. I know the screen works as it showed 02 when I disconnected the battery to clean the posts.

 

get a fuel pressure gauge and check pressure on passenger side of the fuel rail, if you can get a long enough hose on the gauge tape it to the windshield (or hold it in place with the WS wiper )so you can drive it and read it .....it should read in the mid 30's psi , maybe slightly higher under acceleration ......this will help diagnose a weak / failing fuel pump..let us know how it goes

 

Finally got a chance to check fuel pressure, holds right at 33psi or so under load. I don't know if holds pressure at high rpm under load because it bogs, backfires and falls on its face before it can get the rpms up. Revved without load several times in a row and the pressure drops to 25 psi or so but builds back quickly. I started another thread with a little more info (I'm somewhat computer illiterate and couldn't find this one until after I already had posted that other one, sorry).

 

ok....the 2 parts you havent mentioned in the ignition are the amplifier module ( known to fail) and the ignition coil (also trouble) at this point I would suggest replacing the ignition coil ....you dont need a real expensive one...just a known good one. your symptoms indicate a bad coil, usually if the amp module fails > it works until it gets hot, a bad coil can fail at most any temp. My 95 acted the same way, a failing coil will change the energy of the spark to the distributor...and intermittently cause the backfire .....it's not a bad idea to have a spare one anyway. for testing purposes just hook it up next to the existing one for a quick hot lap, you can secure it later if that turns out to be the problem

 

I rechecked the fuel pressure because it didn't seem right. I finally got it under load and the fuel pressure dropped to about 10 pounds. NAPA had a GM pump that fit so I installed and it runs better now, still backfiring on deceleration but much better. The PO changed out the ignition module to a GM style and mounted it next to the coil. Replaced all the wheel bearings and seals but it still has a vibration starting at around 45 mph (doesn't feel like tire bounce). I am hoping to get all the bugs worked out in time to take it on a flyfishing trip to Montana the end of March. I have read that a lot of times the vibration is caused by bad u-joints or drivelines that need rebuilt. The back driveline is not too old from Great Basin Rovers, the front is stock. I got under it and shook everything, seemed fine. I'll take both out and look a little closer. Anything else I should be looking at? Thanks for the help.

 

Check the panhard bar bushings. I replaced mine after many years and the replacements were great for about a month and then it was worse. I think the replacements were allmakes brand because that is what I could get. Ended up machining some replacements from delrin that I had in the shop. Those are still in it at close to 300k miles

 

vibration could also be tire balance

 

Doesn't quite feel like tire vibration, I'm not feeling it in the steering wheel. I adjusted both side mirrors to watch the rear tires and I didn't see any bounce. Would I feel front drive line in the steering?

 

has the rear roto-flex been converted to a u-joint (at the rear diff) ?? the rubber rotoflex is usually a good source of vibration....even if it "looks" ok