Hard to start when weather and vehicle are hot- SOLVED (2 Viewers)

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ColoradoBoy

ColoradoBoy

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Jun 17, 2018
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Been half-heartedly chasing this issue for awhile, but now I've had it! Gotta get this issue fixed. Broke out the FSM, bought a fuel pressure gauge set, and went to work.

Started with pulling the cold start injector (FSM, pages FI-52-53) I cleaned it up not long ago, but figured I would make sure...
1. Resistance at 3.8 ohms (2-4 ohms spec'd.)
2. Spray pattern even and good.
3. I noticed that when loosening the CSI, there was no pressure being evacuated... Not a good sign, I think.

Moved to FSM pages FI-47-49 (following line by line):
1. FI-48(k) tests at 44psi (37-46 spec'd) (fuel pressure with jumper in place, gauge installed directly on the fuel rail)
2. FI-48(o) tests at 46psi (37-46 spec'd) fuel pressure @ idle
3. FI-49(q) tests at 40 psi (33-37 spec'd)
4. FI-49(r) fuel pressure should remain greater than 21psi for a minumum of 5 minutes.

Here lies my question. Fuel pressure @ idle with vacuum hose disconnected from FPR is high; when the engine is shut off, the pressure immediately drops to ZERO. I have no experience with FI systems, so I'm asking for guidance and knowledge, as my searches through the site have not netted me a definitave firm answer in my mind - does this indicate the FPR and/or the FPD need replacing? FSM says check fuel pump, pressure regulator, and injectors. I figure that some guru here (@jonheld, perhaps? 🤞) would be able to give me some insight based on their experience. Knowing that I have a near-30 year old rig, I would like to (but my wallet would not) rejuvenate the fuel injectors as well, but baby steps...

Thank you in advance for the help.
 
jonheld said:
To be clear, you ONLY have issues starting when the vehicle is hot?
If it sits overnight, it starts without issue?
Click to expand...
Yes, that is correct.

EDIT- yesterday was a tough day as far as logistics go. After sleeping on it, I am leaning toward believing that:
a. FPR is done, and has ruined check valve at fuel pump (no pressure held when engine is shut off) Slightly puzzled, as I replaced this last year with a replacement from a donor cruiser, but maybe it failed too...
b. injectors leaking
Cheers!
 
Last edited:
ColoradoBoy said:
Yes, that is correct.
Click to expand...
That screams FPR to me, but that's assuming that all other ignition components have been inspected.
The OEM FPR is NLA, but there are several aftermarket choices.
There is an interesting thread regarding the FPR in the FJ62 forum. Have a read through this:
forum.ih8mud.com

FJ62 Fuel Pressure Regulator needed

Hello FJ62ers..I used this great forum to find the exact problem that my beloved 1990 FJ62 is having (hard to start when warm) .It seems that I need a Fuel pressure regulator but when I look on line all the places say that they are discontinued. Can anyone please tell me a place that that may...
forum.ih8mud.com forum.ih8mud.com
 
jonheld said:
That screams FPR to me, but that's assuming that all other ignition components have been inspected.
The OEM FPR is NLA, but there are several aftermarket choices.
There is an interesting thread regarding the FPR in the FJ62 forum. Have a read through this:
forum.ih8mud.com

FJ62 Fuel Pressure Regulator needed

Hello FJ62ers..I used this great forum to find the exact problem that my beloved 1990 FJ62 is having (hard to start when warm) .It seems that I need a Fuel pressure regulator but when I look on line all the places say that they are discontinued. Can anyone please tell me a place that that may...
forum.ih8mud.com forum.ih8mud.com
Click to expand...
Will do. Thank you, @jonheld!
 
ColoradoBoy said:
Will do. Thank you, @jonheld!
Click to expand...
...but the question in my mind remains- is the lack of fuel pressure at the fuel rail when the engine is shut off indicative of the FPR and/or the check valve at the pump being bad? What am I missing? FSM FI-49(r) says pressure should remain 21psi or more for at least 5 minutes. The lack of pressure in my test has me confused.
 
ColoradoBoy said:
...but the question in my mind remains- is the lack of fuel pressure at the fuel rail when the engine is shut off indicative of the FPR and/or the check valve at the pump being bad? What am I missing? FSM FI-49(r) says pressure should remain 21psi or more for at least 5 minutes. The lack of pressure in my test has me confused.
Click to expand...
EDIT- never mind... I can't read.
 
jonheld said:
Posts #8 and 9.
Pay particular attention to post #23 in that thread. CruiserParts sold him that crap for $50.
Click to expand...
Yeah, they got me, too.
 
Ordering this: Denso 23280-74100, per post #35: FJ62 Fuel Pressure Regulator needed
Like the other thread, I will verify operating pressures once installed.
Again many thanks to @jonheld for taking the time and helping so many of us out!!

EDIT: and a good reminder that even though this is the 80 Series forum, other models have the 3FE motor, as well- SEARCH THERE, TOO!!
 
Last edited:
jonheld said:
Wrong engine. Looking for a 3FE FPR.
Click to expand...

Ah, well then yup, NLA. Another good reason to not buy an FJ80 vs an FZJ80.

I would say you are on the right track if everything else is good, IE ignition/vacuum/ect.

Cheers
 
SNLC said:
Ah, well then yup, NLA. Another good reason to not buy an FJ80 vs an FZJ80.
Click to expand...
Don't be a hater. There are plenty of parts that are NLA for the 1FZ as well.
There are aftermarket alternatives however.
 
jonheld said:
Don't be a hater. There are plenty of parts that are NLA for the 1FZ as well.
There are aftermarket alternatives however.
Click to expand...

Haha, I am no hater man. FJ80's are good trucks. I just don't see why you would buy one when FZJ80's are plentiful and don't really cost more. The 1FZ is a far superior engine not to mention FF rear and rear disc brakes.

Cheers
 
SNLC said:
Haha, I am no hater man. FJ80's are good trucks. I just don't see why you would buy one when FZJ80's are plentiful and don't really cost more. The 1FZ is a far superior engine not to mention FF rear and rear disc brakes.

Cheers
Click to expand...
Wheel what ya got... Have fun doin' it!
 
Installed the @jonheld recommended EFI relay: (28300-16010) and I am pleased to report after several weekends of wheeling, NO issues with my CEL!
It is really nice to not have to pop the hood and tap on it anymore. :clap::smokin:

Got the replacement FPR (23280-74100) and will get in installed and tested- will post back soon.
 
OK, still no love from Sheila.

Installed the above-referenced FPR tonight, but no change in the hard to start when hot. Didn't have time to throw the pressure tester on it yet, but I am beginning to think that the real problem is that the injectors are leaking, which would explain why fuel rail holds zero pressure after the motor is turned off (as far as I can tell from my research and limited testing). I'm guessing the injectors are my new #1 suspect. Again, need time to do a complete pressure test of the fuel system. If it is the injectors, will need to figure out the best way to replace/rebuild in a short time frame to keep my :princess: happy and traveling, as well as dig up some $$ for the project. I really gotta find some money tree seeds... :bang:

I have found that if I let the motor crank 4-5 revolutions and stop, then try again in a few seconds it will fire up in another 4-5 revolutions. My thinking is that the first crank clears the flooded condition and then allows it to start.

Whatever the final issue, I'm getting to know more about this machine. 30 year old rig needs new parts- what a shocker! ;)

I'll post back soon. Happy wrenching (and wheeling) to all!

DSC02590.JPG
 
jonheld said:
If the injectors were leaking, it would ALWAYS be hard to start. Not just when hot.
Click to expand...
Crud. Thanks for pointing out that bit of info. :doh: So if that is truly the case, I believe that leaves the FPD, fuel pump, & plugged charcoal can; & save the injector refresh project for another time...
 
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