Builds SAS 89 Mini--Triple cased Mashed Potato

jynx

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Well sounds like you've been busy. Ive had more than my share of hard starting vehicles.

My old 4Runner was that way. Would cold start like a champ, but if it ran for much time at all, it had a hard time starting, got to where it wouldn't start at all without at least a 30 minute cool down. I ended up replacing the fuel pump before I sold it and it took care of the issue. Didnt make sense since it would start fine. I suspected the pump, but was trying everything to avoid dropping the tank. Might give that a check.
 

TeddyBoy

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Well sounds like you've been busy. Ive had more than my share of hard starting vehicles.

My old 4Runner was that way. Would cold start like a champ, but if it ran for much time at all, it had a hard time starting, got to where it wouldn't start at all without at least a 30 minute cool down. I ended up replacing the fuel pump before I sold it and it took care of the issue. Didnt make sense since it would start fine. I suspected the pump, but was trying everything to avoid dropping the tank. Might give that a check.
See that makes no sense to me at all but consistant with many accounts. That said the timing might be just right, getting ready to replace the factory tank with a bed mounted fuel cell. Seems having a fuel tank as the low point of the rig is probably not the best idea and it is the last of the unmodified systems in the rig so might as well get my paws on it.

anyway..
20191006_104150.jpg
20191006_104211.jpg
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jynx

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Very nice sir. And yeah, the hot start and fuel pump made no sense to me either, but like you, I'm out on electrical gremlins. And if you are doing the fuel cell and all, that should take care of your pump anyway.
 

TeddyBoy

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Running Rich - Continued...

new fuel pump - no change
swapped fuel pressure regulator - no change

from reading the EFI relay is either good or bad, if getting fuel and truck runs it's good so ruling out (for now).


dropping factory tank and replacing with Fuel cell this weekend, perhaps I'll find a wiring issue hidden by the factory tank. :bang:
 
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TeddyBoy

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for my own use later down the road.

ordered (now discontinued) part # 89428-89101 (engine coolant temp switch) from rock auto for $12.

theory being: 3VZE coolant temp sensor control gauge? - YotaTech Forums

When the ECT is working properly, the ecu runs the motor in open loop when motor is cold, using preset values for mixture and timing advance and ignoring the O2 sensor. Then when the motor reaches op temp, the resistance of the ECT changes and the ecu switches over to closed loop operation, using the O2 and other sensors to calibrate mixture and timing.

I think usually when the ECT goes bad, it's failing to change resistance when hot so the ecu never gets out of open loop and you get rich running, bad gas mileage, and your cylinders & O2 sensor get gunked up with carbon. But if an ECT were to give the "hot engine" signal when the motor was cold, then the ecu would try to run in closed loop when cold, which probably would run like caca. I doubt that's common, tho. If it's not running right when cold, probably another cause.
 
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TeddyBoy

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minor updates:

probably the last major component left untouched was the fuel system, that had to change. The factory tank had been beaten into submission and the bottom was, lets just say less than flat. No pic but the bottom had been so badly indented that the fuel pump bracket sat about 2 inches higher than normal.

So, did this.
20191120_172704.jpg


20191120_172714.jpg


There are no baffles in the tank which i have major concerns with, been thinking about adding in some form of these. Shown below is Alltech's fuel cell baffles but these puppies are $200. From research pretty much anything made of HDPE plastic will stand up to the constant submersion in gas. Have heard of wiffle balls, gatorade bottles etc. being used, kinda runs the gambit.

1574347224598.png




Still having issues of hard starting when warm, almost acts like it's hydro-locked when it gets really bad. So far I've replaced the
  • plugs - no change
  • fuel pump - no change
  • 2 sensors on back of motor - arguably minor improvement
  • fuel pressure regulator - no change
  • checked and corrected some vacuum lines - motor definitely runs better but not convinced helped starting problem, not thoroughly tested yet.
  • distributor (last night - motor runs but dont know yet)
Here's the old one
20191120_172748.jpg



If that fails gonna pull the entire EFI system and intake off my spare motor and install and cross my fingers.
 
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jynx

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You may have checked this already, but is the timing correct? I know on the old Ford that Chris has now, that it would hard start when warm and while I am not sure it is 100% resolved, I think it had to do with the early efi attempt in the truck and that because lots of the stuff was pulled off, it was effectively in "limp" mode and the timing was retarded pretty bad. It would cold start great and ran good as far as I could tell, but hot starts could be a real issue. Just something else in the mix, and you may have already checked it, but also, if I recall, on the OBDi trucks you have to put the little jumper in the plug to change the timing for setting the base timing, so make sure you are doing that otherwise your base setting may be off.


P.S. love the ole tater.
 

TeddyBoy

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You may have checked this already, but is the timing correct? I know on the old Ford that Chris has now, that it would hard start when warm and while I am not sure it is 100% resolved, I think it had to do with the early efi attempt in the truck and that because lots of the stuff was pulled off, it was effectively in "limp" mode and the timing was retarded pretty bad. It would cold start great and ran good as far as I could tell, but hot starts could be a real issue. Just something else in the mix, and you may have already checked it, but also, if I recall, on the OBDi trucks you have to put the little jumper in the plug to change the timing for setting the base timing, so make sure you are doing that otherwise your base setting may be off.


P.S. love the ole tater.
Thanks @jynx , always helpful!! Your timing is spot on. (notice the pun)

I have not checked it yet but will be doing so in short order, gotta go buy a timing light first. It's definitely not in limp mode (retained the CEL when new dash went in) and have read virtually every "this is the fix" thread known to google.

Found one the other night where a guy was suffering from similar symptoms and turned out to be 2 issues. The first was a bad distributor and the other was a clogged injector, thus my current thought process.
 
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TeddyBoy

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so checked the timing and holy crap, it was off the timing indicator. For this motor it's supposed to be 10* BTDC and I'd guess it was somewhere around 25*. Read where a lot of guys run it 14-15* with good results so i split the difference at about 12*.

Seems to be running better, lowered the idle a couple hundred RPMs which is also a good thing. Crossing fingers...
 
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