1991MJPioneer

Well first things first I've gotta test the flow rate of my pump. I definitely don't have the money to buy a pressure regulator or a pump or get injectors cleaned. I'm a poor college student so things will get fixed as I slowly accumulate the money :cheers: Theres a book called Jeep 4X4 Performance Handbook that has those formula's in it. I've seen them too on Jeep Strokers forum. Thank you Don :thumbsup:

My apologies - didn't notice you had a 4.5 stroker. :D I'm using the 96-99 Mopar 23.2lb/hr grey tops, p/n 53030778, and running them at 46psi. These provided the best numbers on the Hesco dyno for my particular setup w. the cam, exhaust/intake mods and Unichip I have. If you frequent the stroker forum or the Hesco forum, there are long discussions regarding optimum stroker injector sizing. Most, but not all, if using the Ford 24# injectors, end up running them at a lower pressure than the stock regulator lets them. You might get by using them on your setup, but only a dyno run (not the olde butt dyno) will let you optimize it. HTH......... No problem Don. :cheers: I actually have two sets of the 96-99 grey tops. I bought a 97 block and the guy just gave me two intakes with everything...unfortuneately I don't know what condition they are in. I guess you're running the Hesco Adjustable FPR? and I suppose the guys running the Ford 24# end up with too much fuel if running at stock pressure? is that the later 50 PSI pump or the earlier 39 PSI H.O. pump? Will the factory 21# injectors suffice for now or should I invest my money in a FPR and different injectors?

Ok cool. I'll read up on it tonight. What size injectors are you running in your stroker Don? I've read that guys have used the 24# Ford in strokers. Also my concern was that with my stroker, I'll have detonation issues because I'm running a stock cam and 9.7 to 1 compression. I was thinking that the larger injectors might be beneficial.

Darn...well. I'll get on that flow rate test then. I was considering replacing the injectors with higher flow units anyways at some point. I suppose I could buy new or cleaned up ford 24# injectors somewhere. I'll aslo see if the '91 FSM has anything on testing for flow rate.

Ok. Good news. I have fuel pressure finally and the engine idles. I set the pump in a bucket of fresh gas and pumped directly to the rail bypassing the old fuel filter. It took a good few times to prime the system and for it to hold pressure, but it shows me about 35-37 PSI while running. As of right now, the pump is holding at about 30 PSI with engine off. It might still be dropping as thats what it was doing. I would hope this means that I have a useable pump. The engine cuts out if I attempt to rev it. I suppose this is because the oxygen sensor and coolant temp sensor arent hooked up and it is in open loop. Right? Thanks for the help ;)

Just wanted to know if the pump strainer could've fallen into the tank. It wasnt there when I removed the pump. Thought I'd ask here tho since I'm kind of a noob when it comes to some stuff. ;)

How do you expect it to run if you don't have the engine control sensors connected? :smart: :rotfl2: Yeah I know it won't run all too well without all sensors hooked up. I know the engine fires...I'm not worried about it running perfect right now. I just am trying to figure out the fuel pump issue so I can have fuel pressure. :???:

you said you replaced an o-ring at the fuel rail, any way you accidently got something inthere an plugged it up? like the old o-ring perhaps? Doubt it. I threw the old o-ring away. I had the no pressure problem the first time I tried starting the truck.

So today I took the fuel pump/sender unit out of the tank and to my suprise....there was no strainer sock on the fuel pump... :dunno: I tried looking down in the tank and it looked relatively clean for a 20 year old truck...but couldnt see if the strainer had fallen off somehow. Could the strainer possibly fallen off in the process or removing the pump? I tested the pump briefly while it was out of the truck and it pumps...but I don't know the proper procedure for testing it Anybody?

Yep definitely no fuel pressure at all. I checked with gauge. Also depressed valve on rail with screwdriver and it just hisses and bubbles. I disconnected fuel return line and a little fuel came out but not much. I poured a little fuel into the intake and it fires right away. I haven't checked the timing again yet...but I thought I'd start with the fuel problem. I'm gonna take the fuel pump out and check everything.

Actually... :roll: yeah the fuel in the tank is from last June. I just wanted to see it start and then I was gonna put fresh gas in it afterwards if everything worked. I did a check at the test valve and it showed me nothing yesterday but I'll mess with it again. I'm not 100% positive that the dist is set properly, I thought I set it properly before I put the motor in. As for the dist...it may be one tooth off...its pointing in the right direction and its set at number one end of compression stroke. :hmm:

Well I tried starting my stroker tonight... It seems that everything is functioning but I'm just not getting good fuel pressure to the fuel rail. Fuel pump is working and is pumping fuel. It is noisy though. It was just as noisy as when it ran last summer. Tonight when I cranked it over, it fired a few times and then started spraying fuel from the pressure regulator on the fuel rail. I went to the parts store and bought a new o ring...it stopped leaking, but now its not firing at all. Good spark as far as I can tell. Engine malfunction lamp is blinking also... Could my problem be partially because I don't have the oxygen sensor hooked up along with the coolant temp sensors? I don't really know where to start. Could my fuel strainer sock be plugged up? the truck has been sitting since last June.

Yeah H.O. Looks like this...

Sorry. The teeth for the CPS arent on my 91 flywheel, Instead, they are smooth.

I know that the flywheel on my 91 H.O. does not have the upper notches. They are smooth. So my guess would be that it is a Renix.

I've got a 29sp 8.25 sitting in my garage...got it dirt cheap too....unfortunately it came out of a 97 2wd with AX15 so 3.07 gears....I looked at shafts once for the 8.25...Superior makes stonger shafts for it. Yukon did too....

The aluminum cover does have baffles but are located only just below the breathers and not the entire length of the cover... Advantages/disadantages? well the cork gasket for your '92 is alot cheaper than the rubber gasket for the '01...also supposedly valvetrain noise is less noticeable with the aluminum cover... As far as I can see....it is a direct swap....the two covers just use different gaskets and breather grommets.

Yup... :agree: I'll try that first...I'll get to wrenching on the MJ again tomorrow and see what happens!! Thanks!!

Will do. :thumbsup: old standby haha. Will dropping the trans a little give me about the same clearance as I would get if I removed the motor mounts and jacked it up?

Thats brilliant ;) ....Will def do that next time I have to deal with removing the trans from a cherokee with a 4.0.. If I remove the crossmember to lower the trans a little for more access to tighten the bolts, what do I need to disconnect? Xfer case linkage? I don't think I'll be dropping it much...just enough to get an extension and socket in there... Thanks guys

I tossed the inverted torx!!!! got hex heads...There seems to be no obvious way to get them in with the engine in its current position....the bolts get caught and I have no room to manuver...I'll find a way somehow... Yes I checked the reservoir and filled...no more leaks...will see how it goes once the truck is driving....

Well...I got the new motor set in the engine bay. I never removed the trans during the install. I got the two bottom trans to block bolts snugged up, but I'm wondering whats the easiest way to get the top two in??? do I need to lower the trans?? Also. Right after I got the trans bolted to the engine, I noticed hydraulic fluid leaking from the bellhousing. It leaked very slow for a day....then stopped. :hmm: clutch pedal is still firm... Any ideas??

That I will have to check the books on, but I know the one book listed the 3183 for '92... Let me check my archives. Rob L. Sweet. Thanks!!

So according to automans's website....9,576 MJ's were produced in 1990....how many of those were actually '91 models?

LOL, sorry :rotf: :fool: So, someone on here not too long ago posted something about the "official" CFC MJ count. Where was that source from? I did a brief google search of scrap vehicle records and found nothing...does anyone know of any website that maybe keeps track of year/model scrap certificates? I would imagine there has to be some record of every vehicle destroyed; maybe something a classic vehicle appraiser might have access to? If so, I think that would be MOST valuable for determining the rarety of the 91/92 MJ's...you know, once we figure out the official number made, then subtract the fallen ones to see just how many of them technically still exhist :dunno: I'll keep digging. -James The official number is the one I posted for '92... 3183 or something... I have that backed up by a couple jeep books that correspond. Rob L. :shake: its all good James Yeah I have found 2 pics of a 1991 MJ like mine...shortbed 4X4 Colorado red....etc I agree that finding the number of scrapped MJ's would help alot with knowing truely how rare certain models are....My MJ was manufactured in september of 1990 but was a 1991 model.... what month is the cutoff for the next model year? July???? I think thats what it was... :dunno: