Can of worms... warm temp stall issue

Well I have the dreaded 'stalling' condition when my rig gets to running temp (185-195ish).
I am writing about the fix while I am waiting for parts to come in the mail.
This is such a can of worms since battle wagon's motor has been modified in almost every system. I have the full Renix system working with an HO head with chevy valves, 2000+ intake, 95-99 exhaust header.

Things already done/thrown at it:
new Crank Position Sensor
new Cam Sync Sensor (or magneto as the auto zone guy called it...?)*** it was the correct part no matter what he called it ****
new fuel pressure regulator (1988 Renix fuel rail... Yes, it works.. odd how so may folks claimed I had to switch to a newer 95+ rail.) I have the HESCO AFR also, but I put the stock on for trouble shooting.
new TPS and adjusted spot on
cleaned out the IAC... going to do it again because I have time
Going to buy a new ECU since it is only $90 at Oreilly's now (wasn't it $600 before? same part number also?!)
new O2 sensor
new 10mm spark plug wires
new distributor cap


in the mail:
new ignition coil
new fuel pump from spectra

I am thinking I have a bad check valve in the fuel pump (original 1989 pump). I disconnected the fuel return line from the regulator and it drained so fast that I could hear the vacuum building as the fuel travel back into the tank! I thought the fuel was supposed to stay put and not back flow? I have an inline check valve on the supply line before the filter and after for less mess when I am changing it.

My plugs are all gapped (stock gap) the same and look normal.
I do have the Ford Motor craft 30lbs injectors that I just had rebuilt and flow mapped 14 May. (30lb @14.9ohm 43PSI) AUS Injection in Phoenix. I have a 5 liter stroker so I went bigger than 24lbs to feed the beast.

I just drove from Phoenix mid may to Virginia and it ran perfect all the way. I get to my destination at Fort Lee and the problem began.

Anyone got any clues/experience while I waste time waiting for parts?

I am thinking that the ECU begins management after warm up and tries to correct fuel pressure? (lowers from max pressure (39lbs) for start to around 31lbs for running)... not verified since I cannot check pressure while driving.
Fuel pressure will drop immediately after I shut down, hence my thoughts on bad fuel pump/check valve.
the lower pressure from pump may be messing with the injector cycle?

Dave

Well zero residual pressure is yummy 2 minutes after shut down


And 9-10 lbs during operation is not good either



Fuel pump shows up tomorrow

well all I can say is I have had an 88 XJ Renix since 2003.I recently purchased a "96" strictly to get away from that French built POS System.I have been a master ase tech for 28 years and I am just sick of dealing with it..number one mainly...start up imediately goes to 3,000 rpm I have gone though EVERTHING on this vehicle...done with it.GOODLUCK:shiver:

Disco the 3-pin connector from the tps. Should solve your high lide problem.

I have done that..but it is not a permanent fix.I did however fix my agravation by disco-ing my self from the drivers seat...

Not likely the ECU. And, Renix goes into closed loop very quickly if your O2 sensor is good. Less than a minute. The fuel pressure is not eCU regulated. At high vacuum, fuel pressure is reduced, low vacuum is reduced.

Have you ever explored my write-ups for typical Renix grounding issues? They can kick your butt if not addressed.

Click on the following link and perform the procedures in posts # 1,2, 3, 4, and 5.

Ha! Too funny you mention the grounding. I am currently following that thread and fixing grounds. I used the search and found it. I have replaced all the big stuff with battery cable stuff (firewall, battery to firewall, head to firewall, block to firewall, and rad cover to firewall) now hitting all the smaller items to fix any gremlins. I think I have something grounded out though... Should the negative cable 'spark' when I am hooking up the battery?

Dave

Ooops. Here's the link.

http://www.cherokeeforum.com/f51/cruiser54s-mostly-renix-tips-153657/

A small spark due to small electrical draw without key on, yes. Clock, dome lite etc. Get 'em all clean and see what happens.

Wow! Can of worms indeed! Look what I found in my gas tank. This pump died at every location possible. I especially love how the feed tube is not connect/failed rubber.... Notice the missing worm clamp? Mmm that is gunna be fun fishing out! the filter sock is totally black, yes a few years ago I had serviced the tank and that used to be a different color.

New spectra pump next to old for reference... Yummy

New pump installed. Pressure right at 44lbs! Yay,party1:
I may readjust up to 49 psi to get my full 30lbs out of my injectors... Still deciding and will have to run some tests to see what major differences will be.

Oh, and yes in the photo is the infamous renix fuel rail working just fine on the 2000 intake. Please stop messaging me about how I am BSing and that I have to use the 95 rail... You know who you are.

I forgot how fun Battlewagon was to drive. Now that I am back in the 'garage' tune zone with this motor the power has stepped back up. I still need to retune my AF with the O2 analyzer so I can dial in the adj MAP. It was nice to burn the tires a bit from a dead stop, haven't done that in a while.

In summary:
1. Check fuel pressure
2. Clean all grounds that Cruiser54 has on the link he gave me.
3. Voltmeter to the TPS FLAT connector not the SQUARE one.

Those 3 steps will direct you to the exact problem!

I do not think the Crank Position sensor (CPS) is a top three check since the first three are Fuel, Fire, Air. I disconnected it to see if it led to a warm stall, and it did not.

Idle Step Motor also was a non issue for warm stall, just bad idle.

Camshaft Position Sensor (CKS, Sync Sensor) was a non issue for warm stall. The little magnet is what fails the most in these when the original glue wears out... I just re-epoxied my old one and it works just fine. Clean and sand the metal housing that covers it, since it was that thing being dirty and knocking off the magnet from the holder.

Exhaust leaks also a non issue for warm stall. Best to fix those anyways.

Vacuum leak also non issue for warm stall.

MAP sensor tube also a non issue for warm stall. Just bad idle and AF ratios, runs like crap without it, but it still runs.

I am listing those since so many threads have tried to hammer each item as a symptom for the warm stall. Once I got the XJ running good I went back and individually tried to cause a stall event from those items.

If you have never changed the sensors on the older XJs, spend the cash and service each one just for longevity sake.

Dave

PS If this is your problem, just PM me with Warm Stall on the subject and I will get with you to help you get back to normal.