Dando

Thanks, i will try to replace the MAP with another one i have in my parts stash and see what happens. I know the vac line to it is good for sure.

Just went through all the work to replace my broken one with an aftermarket ATP flex plate. my truck now runs but misfires terribly. Looking for a factory flex plate now as i know that one will be clocked correctly. Anyone have one laying around? And honestly the cheaper the better as without the truck running i have been unable to make money. Thanks. I'm located in zip 44111, for shipping.

Can you explain that better for me? i guess to don't see how it would change the indexing but not the timing?

Already did that too, it was tight where it was suppossed to be. Does anyone think cutting the distributor mounting tab and spinning the distributor body would make up for a slightly incorrectly indexed flexplate?

Ive checked and double checked all the vac lines and electrical.

Ok so I tested my tps, it checked out fine but I replaced it anyways as I had a warranty on the one I had. New one adjusted and whatnot, still no change. Idles fine at around 900 rpm. If I rev the engine at all it misfires, wide open throttle to get past it and the Rpms shoot up past 3k rpm and it runs fine at that engine speed after I've gotten through the bad part. The exhaust currently isn't Hooked up past the manifold, all connectors have been checked (unplugged cleaned and reconnected), throttle body clean, new cap and rotor, new plugs and wires, I'm at my wits end with this truck. I'm broke and the truck is a huge problem for me. I need to get this figured out. How can I confirm or rule out my new flexplate as being bad? And without cutting the tab on my distributor everything lines up like it should according to cruisers tips. Should I cut it off and try to change it?

Will this work with a digital meter? And if so what readings should I see?

After playing with the tps flat connector some more, I've been able to get it to idle high (2krpm), it will idle normally after connecting and reconnecting it. No matter where it idles as soon as throttle is applied it acts up. I'm starting to suspect a bad tps? A new one won't be in for me to try till morning.

Ok so some progress. I have filled the trans, it had no affect on the issue. It's still idling strong but once off idle stumbles like hell and backfires a bit etc. I set the engine to cyl 1 tdc and checked my distributor, and the trailing edge of the rotor is right where it should be. Just to check I Installed it once 180* out and it wouldn't run at all (obviously). I set my tps with a reference voltage of 4.88v and a output of .82v and still no Change. The truck moves in drive/reverse etc as long as it stays at idle, what else can I check?

Is there a way I could determine if that was it? And I'll ask this again, could the fact that I haven't filled the transmission with any fluid yet have any effect?

Nothing seems to change with the tps unplugged. Tested tps and got 4.88v on the "a" side and .79v on the "c" side

I should add, the aw4 currently is empty of fluid, I thought I had some dex in the garage but I didn't and will be buying some this evening. Would that cause this?

As an update the truck starts up and idles fine now, still the stumble if throttle is applied. Wish I had a multimeter on me. When I installed the new flexplate there was only one orientation that would allow all bolt holes to line up. Going to look into the different methods on how to verify my timing against the flexplate. how would I fix it with the distributor if I do find it's out of time?

Ok help needed, I finished the flexplate install just about 30mins ago. The truck starts and runs now, just not well at all. Idles terrible unless I throttle it. When I throttle it it stumbles until 2k rpm then it runs smoothly but sticks at a high idle. Don't have my multimeter till after 5 bc I left it in the fiances car. Sounds like maybe a TPS issue to anyone? There seemed to be only one way the flexplate could be installed so I don't think it could be out of timing.

As I've been thinking this work over for abit and really being picky about the part I get, I ended up with an ATP part number Z-205 and as far as I can tell it's identical to my broken stock unit. But I think my issue stems from a catastrophic failure 4-5yrs ago now when I had first got the truck on the road. I broke a u joint and lost the rear shaft (when it was 2wd) doing around 60 on the highway. The resulting impact broke the bell housing, and god knows what else. Instead of repairing it I just started my 4wd swap instead and scrapped the 2wd trans. In that whole process I never really went over the flexplate, just changed what I needed to and got it on the road quick. After that it has had intermittent issues ever since, looking at the flexplate I just pulled out it's got all kinds of cracks and the center section is completely seperated. If I had been more focused I probably would have seen small cracks in the flexplate years ago, but honestly I was in a rush to swap an engine and transmission in two day and too distracted to take my time like I should have.

Thats kinda what I'm afraid of, i found that old thread which lead me to this confusion. So locally the only option i have is a part made by pioneer, pn FRA-333.

Thanks that pic comparison should help a lot.

On my 90 4.0, my flexplate it cracked and seperated from the center section completely. I have read conflicting reports about some replacement parts not being made properly. I don't want to install a bad part. Anyone have experience with any manufacturer? Can anyone tell me one they have bought that worked for sure? Don't want to do this job and afterwards find out it still it's right. Thanks. Locally I have options from autozone, advance, orielys, etc.

Thanks everyone, Gogmorgo - no need to find the part numbers, I swapped those quick connects awhile ago in favor of AN fittings on the transmission an it's lines.

So I'm mainly asking if the flexplate could have caused my original issues because either way I have to replace the flexplate. Just trying to decide if I should replace the motor as well. I'd rather not replace it as from what I can tell with the valve cover removed the valves etc seem to be working properly. Just don't want to pull the transmission just to fix the flexplate and then find out my engine is junk now too.

So large change in the problem yesterday. The truck was running fine, I go to merge onto the highway and the engine seemed to cut out for a second then started running severly underpowered, barely able to get it off the road. After getting it towed home I tried to start it again and it started and ran like total crap, barely would idle etc. I walked away out of frustration and came back to it a few hours later. When i I cranked the engine the starter spins but the motor didn't. After looking through a bunch of things I've determined the flexplate is broken (seems like the center is broken and no longer connected to the outer ring and thus not allowing the starter to move the crank) I can spin it by hand with no resistance. Turning the crank pulley with a wrench and it seems the engine itself still has compression etc. Well obviously i wilI need to source a replacement for a renix motor, which I've read can be a crapshoot but that aside. Could a cracked and broken flexplate have caused my original issues? Throwing the timing off?

Whichever the original is, probably the synthetic blend. Puralator filters. Changed every 3-3.5k miles.

For about 10yrs now I've been running this engine on valvoline maxlife, if that's not considered a "better" oil, and I know this is opening a can of worms, but what would you suggest otherwise?

Thanks I should have said before trying the oil/ATF trick, I split a can of seafoam through the fuel tank and the cranckcase, and another can down the Intake. It didn't seem to help at all. Thats why I tried the ATF mix.

So I've been having an issue with my 90mj (95 xj 4.0/renix intake and sensors) this 4.0 happens to have close to 500k mi on it, it got all new gaskets, oil pump and timing gears/chain about 5yrs ago when I swapped it into the mj. Anyways, a few days back now it backfired and started to run terribly. After sorting through cruisers tips everything checked out so I moved on to pulling the VC and checking the pushrods for straightness and valves for movement, everything checked out fine. At this point I was betting my lifters were messed up. As a last ditch effort before pulling the head I did an oil change and used a mixture of 10w30 and ATF on the advise of my old man to help clean out the engine internally. This seems to have worked, it didn't at first but after revving the engine up pretty high it now runs perfect even at idle. Any thoughts on how I can prevent this from happening again/keep my lifters from sticking/clean out the engine better without a rebuild?