03 Isuzu rodeo,3.2 Doha v6, fresh rebuild, runs great until closed loop

Newbie here. 40 yrs ago i rebuilt engines for hobby. Had kids, been out of it till last year. Now doing charity rebuilds for good people on min wage, trying hard to make it. Me too, but that’s another story! Bought dans book and ebook, but hoping for a fast fix since this girls been waiting for 4 months to get the rodeo back. Here goes, complete rebuild, machine shop, and felpro kit, Hastings rings. Motor had major head gasket leak. Left side, as is common with this engine, but no cracks in head. Reassembled, runs great, had a couple codes at first, but rebooked o2 sensors in correct order! Now no codes. Car runs great, until, I’m pretty sure closed loop. Then dies. Won’t restart, and starter makes weird sound. I first thought it was cam gears, but garden hose to ear test, (im going deaf. Really! It’s only rock and roll) confirms starter location. Let engine cool, boom starts immediately.
Fuel pressure gauge, shows 2-5 lbs of fuel pressure consistently. Just put in new airtex fuel pump, shoots fuel across yard, except when i was in the way.:sick: . Still no pressure, clamp off return fuel line, goes to 50. Replaced regulator, ac- deco, still 2-5 lbs on gauge, drove around block, got to temp, boom dead.
So, i do understand what the sensors do, elec eng degree, although, didn’t use it. Still pretty adept at electronics.
Any ideas where i can start, the neighbor likes to call city code on me, because she literally thinks a blade of grass out of place is criminal:blink: , so the sooner i get this running, the smoother life will run for at least two people. Me and the sweetheart, that owns it. There’s no hope for the neighbor.

Sorry, didn’t mention, i cant figure out why there little fuel pressure. Am i missing something, that helps the fuel control pressure. It is getting vacuum from the line coming from the back of the manifold. Disconnecting this vacuum line, doesn’t do anything for pressure. Also, since there’s no support on the analyzer for fuel pressure readings, I’m guessing the ecu doesn’t have a sensor to adjust pressure. I’m asking, let me know if I’m wrong.
Thinking low pressure is reason for ecu shutting down car,
My gauge works, because pinching off line shows approximately 50 on it, so I’m guessing the pressure is low. Checked new for for leaking diaphragm, looks perfectly dry.

Not sure this will be any help or not, but I looked up the electrical diagram on this car and the first thing that I noticed was that the O2 heater circuit gets its power from the Fuel Pump relay. Since you mentioned that as soon as the O2 gets to closed loop the car dies makes me a little curious. If this was mine, I would look at the blk/red wire coming out of the fuel pump relay that supplies power to the O2 heater fuse 20A and the fuel pump fuse 20A.

Hope this helps.

Going to check tomorrow when it warms up, the weather i mean. Thanks, will keep you posted

2-6 psi of fuel pressure is certainly not right and would be where you need to focus. I don't think It would run at all with that low of psi which makes me think your gauge is wrong.
When it dies and does not start, what is your fuel psi then? Do you still have spark?
If you spray a fuel source into the intake can you get it to start?

Ok , let’s try again. Took a video tonight, where i hooked up a vacuum gauge and showed the fuel pressure on the video. Tried to show the o2 numbers with the fuel trim on my scanner. The new FPR I put on the other day after the fuel pump was my response to clamping the return line and watching the gauge respond with a reading of over 50. So, today i thought maybe there’s not enough vacuum to operate it. I hooked up the mityvac to the line running to the FPR. No change jumping the vacuum up. I was about to pinch the return line, when the car did the usual shut down. At the end i of the video, i tried cranking it and it responded as normal, with the starter barely working with that clicking sound. Engine turns but , with that strange clattering sound, i figure it best to wait till it cools and then restart it as normal, like the beginning of the video. I’m going to submit this paragraph, then try the video, because both together wouldn’t download to the website. The end of the video code was .mov and it wasn’t listed in the approved formats. I may need my son to help when he gets home from work:unsure:

I’m going to definitely need help downloading video. But Just went out to restart. It cranked right up, sounding normal, without that wierd clacking sound from the starter. Then went ahead and pinched return line. 70 lbs of pressure. Analyzer started giving different readings, possibly better, but i had a leak appear where the fuel rail ends right after the regulator. Not good since its down behind the intake manifold, where it’s inaccessible. Shut off car till tomorrow, when weather is warmer. Thanks so far, glad to be a part of the DANNER CULT!

I’m back, same problem. Since last, i took off intake. Hooked up fuel rail to lines from fuel pump at top of transmission, normally inaccessible with intake there. Changed fuel filter. Turned key, 15 lbs at KOEO. Reassembled, engine runs great. 35 lbs, Wow, until 3 to 5 min. Shuts off as before. Won’t restart, makes weird clicking sound like starter solenoid being controlled. Starter won’t engage. Cool for 30 min, same sound mixed with starter engaging, but no start. 30 more min, starts perfect. No check engine light when i restarted from removing intake manifold. This process is consistent every time.
Just went out and restarted with new noid light hooked up to #4 injector, started perfect, noid light consistent flash.
Battery fully charged.
Just restarted, 5 min after noid test. I didn’t let noid test, go long enough to warm up engine. Engine started perfect, just as with noid test start 5 min ago. Ran to temp gauge movement, kept foot on gas for high idle, engine immediately started to stutter, lights on dash, was able to keep running with pedal flutter for 5 seconds. Shut down. Won’t restart as before with clattering sound. Considering the ultimate disgrace, tow to honda dealership. Help

Reread post.took off intake, to hook two fuel pressure gauges to fuel rail, one in between pump and rail and one after rail, to be positively sure about pressure before going any further. Owner of machine shop was going over issue with me and mentioned hooking up line backwards could be reason for no pressure. They were hooked correct. filter was replaced a year ago by me. But changed it anyway. Always believed in not being a parts changer for decades, but with this issue, everything got changed! Now there’s at least some pressure

The "clattering" starter makes me think there is a voltage problem. I am wondering if, maybe, there is a heat/resistance problem. Check the powers, grounds, and starter feed at the PCM, after the warm up.

Could this be mechanical issue? I am thinking when the engine gets warm it start to * seiz * and shut down, then the starter struggles to crank it again and making those sounds? I know it sounds stupid but can you try to turn over the crankshaft pulley after the engine dies and see if there is any resistance.
Also what unit is your pressure gauge showing, Bar, PSI...etc

I agree with pole that you may have a voltage drop issue we see this sometimes after engine replacement , make sure you have a good ground to engine and to body and Frame (I like to test this by adding jumper cables from ground on battery to engine see if any change if not move to frame and so on) if no change try a jumper from b+ to starter or wherever main batter cable goes

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Damnit, typed a long thank you to pole, Ben and pinto. Login timed out, lost the whole paragraph!
Hooked up jumper cable to battery neg. and fuel rail. First start of day so i knew it would crank and run. Ran 200% longer. Temp gauge went to 40 % , and stopped. O2 sensors started reading on analyzer. Thought it was fixed. Rpms at 35 to 4K were smooth until, about 5 min in. Stutter, lights for reduced power, cruise control, and CEL, which would go off below approx 2500. Engine shutdown.
So i put wrench on front crank bolt, to test pintos theory. Turned fine. Glad that one didn’t pan out, no offense pinto! Stayed up half the night sweating that theory out!

The o2 and trim looked good from what i learned from DAN’s book. There were no stored or pending codes.

Clattering and no start are still happening. I hooked up second jumper cables ( left one i was using for neg battery to engine) from fully charged battery to one in car, which charger said it was at 95%, still clattering.
I’m letting it cool while i run errands

I just started it again after cool down. I stand corrected on o2 sensors. 0 reading so tonight I’m going to check voltage to them. Dave 101, you were the first poster to reply, I’m going to follow the wires! Although they were reading yesterday. Not on the HF analyzer, now. Fuel trim hovers close to zero. I got a blue driver a week ago. I think i can figure out how to send data to the internet with my droid from the blue driver scan

Obsessed wrote: The o2 and trim looked good from what i learned from DAN’s book.

You mean Paul's book? ScannerDanner's name is Paul Danner.

Thanks so far! Today, i pulled out computer to check ground in fender. Looked great, gave it a twist with the 10 mm for a what fer”. Rebooted air cleaner housing. I I started car, ran great. Fuel pressure 32 lbs. smooth idle. Rev fine. HF analyzer showed o2 sensors working. Son came out, said “runs great”.
Dash lights, stutter, for 2 sec, shutdown.
Clattering starter, no noid flash on 4 fuel injector.
ECT sensor was showing 176 temp at shutdown.

Disconnect

Disconnected battery for 1 min. Starter cranks properly but no start. No light on noid for #4 injector during crank. Disconnected battery again. Started this time, I disconnected IAC plug for kicks. Engine idled up slightly. Didn’t idle down when reconnected. Son pushed gas pedal to see if that would reactivity IAC, no response from action, engine shut off.
Is it possible the ect sensor is bad. It did take the brunt of the overheat when head gasket went.

Also the jumpers from the neg battery terminal to the engine seemed to be helping with the improved engine runtime, but I’ve not had a chance to go back without it to check for sure.