jeetS

Truck has among other things:
New fuel pump
cold start time switch
injectors
dizzy/cap/wires/
few months old o2



I wrote this a few days ago….

So I've been battling one issue or another on this truck seems like since the day I got it.
A few months ago I finally figured out my cold start issue(bad wire between switch and csi injector) and I had it temporarily wired in it started flawlessly for months

Fast forward a few months and I replaced all my injectors and it started even quicker (a few times) but ran super rough at idle etc.

The starting has been getting worse and worse till yesterday some lights (turbo/brake light) started flickering while cruising...indicating to me a wiring issue.

I started poking around and turns out that the red wire running from battery to fusebox was barely connected! Problem was at the battery disconnect switch, I eliminated it.

So I'm thinking that the starter was getting power but the ecu wasn't therefore making it almost impossible to get going untill the alternator made enough power???

Right after I eliminated the disconnect switch I tried cranking it and it felt like the CSI was now getting power...but it still didn't start right away...untill my buddy touched the wire and it started smooth and perfect...


I'm thinking that maybe the other endo of that wire is not great where it connects to the fusebox...I'm going to check that out when I get some time... Right now the truck will idle nice and smooth then the next traffic light will be super rough and almost die then be smooth again a few minutes later(all at idle)

At WOT yesterday it was perfect. Today it misses terribly after 3K rpm...

jeetS

This was yesterday:

So just finished splicing the new wire in. I used some 8ga wire that I got with an amp and soldered it into the white wire that feeds the 80amp fuse. I couldn't replace the whole thing because it is crimped onto a copper plate that the fuse is bolted to along with a few other wires.

It fired right up as soon as I turned the key. It was sitting for two hours after I started it to move the 20ft into my shop so it was stone cold. Thats good

It also didn't miss at WOT after it warmed up.

After I got home from the test drive it idled fine for a couple minutes then all of a sudden idled super rough…like 100rpm misses…. And under light throttle in the driveway in neutral it was missing like crazy all the way to 3k rpm… It did this till i finally turned it off.


Im done for the night and running out of hair.

jeetS

this was today:

Went out and started it this morning...no dice.
Still took a half dozen tries.

Which leads me to wonder: maybe my fuel pressure regulator is intermittantly acting up?
Too much fuel pressure at idle and bleeding off pressure overnight?

I'm starting to go crazy...


Before I replaced the injectors, when I had the cold start injector ghetto wired it would start up two seconds after turning the key...always
When I replaced the injectors and rewired the bad wire from the CSI to the switch it would start instantly...I could tell the old injectors leaked a bit.
Except for most mornings I would have to crank it over several tries. However after it had sat 9 hours in cold temperatures at work it would fire up perfectly. Only overnight would I have issues.

This gradually started to change...now whenever the engine is cold It takes several tries.

Except yesterday after I fired it up for 25seconds to pull it into the garage (built fuel pressure) then let it sit for 2 hours it started perfectly.


I know that wire needed to be fixed cause it definitely had a bad connection... But I think I have multiple problems at once.



Thanks to anyone who takes the time to read my long and winding problems and offer input...


That FPR looks like it might be a pain to replace with the upper intake installed

I JUST WANT TO DRIVE IT! Lol

jeetS

Well I got home and jumpered the fuel pump connector for about two minutes while I checked for leaks anywhere.

Fuel pump turned on fine and there were no leaks. Tried to start it and it took about 10 tries. Took it for a run around the block (still cold) it drives fine. Let it idle for a few minutes.


It was idling around 1300rpm and the temp had climbed to about 130F and all of a sudden, like someone flipped a switch, it started to idle SUPER ROUGH around 700-800rpm and I could smell fuel in the exhaust. This change was instant!


WHAT COULD IT BE!




Saturday I will verify that the cold start circuit is still working….

Im starting to be tempted to stuff a rag in the tank and let er go….
Im super anal about these issues lol

westjohns yota

replace your fuel filter? have you drained your tank lately? my drop it and see if you have garbage in the tank, check your fuel lines all the way from the tank, could be dry rotted cuaseing an air leak at certain times? just start elminateing, maybe check ur o2 censor and some other various parts, sounds weird to me, this is why i like carb motors over efi anyday!

4wd4fun

so nice to know what it's done before but what's it do now?
cold start 1st in the day ... what happens?

jeetS

^ did you read what I wrote? Cause I don't understand your question...

skypilot

iTrader: (1)

I hate throwing money at problems. the engine just has no fuel pressure test fittings. There is a vsv switch to increase fuel pressure when cold. When it warms up the vsv drops the fuel pressure back to what should be "normal", but in your case might be too low, as in uder 30psi, vice ~44psi running. Perhaps you could put a handheld vacuum pump (brake bleeder) on the vacuum port at the back of the fuel rail and see if the rough idle goes away when exposed to a few inces of Hg?

could be a weak fuel pump, a regulator, vsv,bad fuel lines, clogged filter, and of couse no codes....

Filters are cheap and should be changed once in a while. I think Acton brand has a pressure tester kit that would work, from Advanced Auto Parts.

I am replacing my fuel lne wth AN fittings & -4 nylon line w/ a pressure test port & filter just for this reason.

4wd4fun

yeah, i read. so things have changed, not changed and ....
i'll re-read. no fret.

4wd4fun

so, time switch gets volts when you crank the engine and the time switch resistance allows volts to the cold start injector when the engine is cold, right?

jeetS

yes, but the time switch and injector only receive power when the key is in the START position.

So if my cold start system is not functioning again then I have two separate issues. The sudden rough idle(rich) and the cold start.

If the cold start system isn't working thats not an issue for me, I can fix that. However if the system is working fine then the cold start issue is probably related to the idle…

Thats my thought process anyway. I will find out about the cold start system on saturday.

jeetS

I was under the impression that the fuel pressure up switch/system is for hot starts… Are you sure that vsv is supposed to increase when cold?

When it idles rough I can smell fuel…so that leads me to believe that it is running rich…

The filter was changed about 5k miles ago…maybe its worth looking into…



Thanks

jeetS

So I spent more time on it today.

Checked a bunch of grounds. They appear fine

I pulled the CSI while cranking it and there was no fuel spraying. however the fuel pump was creating pressure. It started when I gave the injector power from the battery. I think I can sort this one out now as I now have a pretty good understanding of the wiring for it… That means the cold starting is not related to the crappy idle that has just developed this past week.


The truck idled rough and it got worse and worse as it warmed up. It smelled rich too. I pulled the vacuum line off of the fuel pressure regulator and the idle smoothed out a LOT. Wouldn't removing vacuum from the FPR INCREASE the pressure?? Im confused. Maybe it smells rich but is running lean?

I checked the EFI temp sensor, TPS, AFM and they all check out ok according to the FSM.

I think I'm gonna replace the FPR tomorrow and see what happens…..


I hate spending HOURS on a problem and getting nowhere.

nhughes

I am having similar symptoms on my 86 22rtec. Sometimes runs ok. other times misses alot under ligh t load and sometimes falls off @ 3k rpm. it seems to be a fuel issue based on afr and experience with failing pumps. pump is a couple months old. I'm beginning to hope it is the fpr.
any update?

jeetS

New FPR didn't solve anything. 1 year old Denso pump.

Wideband seems to indicate lean at idle but super rich at load…. but thats checking the "burnt" mixture…unburnt fuel isn't in that equation i believe

I'm starting to look into the ignition side, going to swap my coil out today….


Im still trying to figure it out

good luck!

jeetS

update is I solved the cold start issue. its unrelated to the rough idle/bogging/cutting out.

swapped the coil out today, no difference. It starts up from cold and runs perfectly smooth for about 20 seconds then all of a sudden starts getting rougher and rougher. AFR's start at about 12 then as it gets rougher it gets leaner. Spiking to 16 a split second after it misses.

Still trying to find an ignitor. Fuel pressure adapter came in. Going to check that this week. Hope to get my air compressor back from the job site soon and do a leak down test to rule out anything there.

jeetS

heres a video showing the idle and afro's

https://www.youtube.com/watch?v=eJxO...kkR2whj-Xk1fbP

when its under load the gauge pegs 10.0:1 ….which is as rich as the sensor will read so its probably richer

RiverRat Cargel

What king of MPG are you getting? I have been having similar issues on my 4Runner. I dropped and cleaned tank, checked pump, verious new valves and sensors still with no luck. Going to try a few of your tricks this evening and new cold start sensor.
Also, I only get 11-12 MPG

Cadin

Updates?