BajaRunner

My truck seems to have trouble starting when cold, and I am fairly darn certain the starter is fine. It feels like it has plenty of power, and turns quickly.

The motor just isn't turning over easily though. When it does, it has low idle (smooth though), for about 2 seconds, then jumps up to about 1600 RPM as it should as it warms up.

Its almost like a sensor is not getting a reading for the first few seconds.

What I've done:
Cleaned IAC, Throttle Body, MAF and did Sea Foam Treatment
New NGK Plugs and Wires
New Fuel Filter

This weekend, I am going to Ohm out the ECT (still haven't actually looked for it), TPS and MAF.

I also think it might be fuel related, but not due to the filter or pump. Are there places to look for a fuel pressure leak when the car has been sitting? (Fuel pressure regulator?)

Thanks for any advice!!

wifes4now

before you start it
turn the key to the on position and wait a minute before you try to start it
this will give the fuel pump a chance to build fuel pressure (i think)
see if that changes anything

BajaRunner

Good call, Ill check that.

Also any idea where the check valve is for the return line?

tunnelmotor99

The fuel pump turns on when the key is in the run position and runs for a few seconds to prime the system. You may be able to hear it if you're in a garage or somewhere quiet. Once the engine is running it stays on, obviously.

LifeOnABoard

This is a difficult question to get answered here. Checking fuel pressure is just a PITA on these engines so no one does it.

See here https://www.yotatech.com/forums/f2/h...essure-215419/

Every other car in the world will "prime the rail" when the key is switched to 'On'. But with my ECU and one from ebay I get no priming, nothing. I have to ground the wire that goes to the ECU to simulate what it's supposed to do if I want pressure before cranking. I did that for a while but it didn't help the slow start. The spark is delayed, not the fuel pump.

See here https://www.yotatech.com/forums/f2/c...estion-209244/


I will be changing the timing belt within the next 2 months, there is something else I can check in the process. Hopefully it reveals the missing clue.

BajaRunner

So you never figured out your long start issue? Yeah I automatically thought it was a fuel issue myself, and haven't ruled that out yet.

Reason being: If I start it up after a quick stop at the gas station, or store, it will fire right up after 1 turn of the starter motor. I do not know what is causing it to hard start when "cold". I'm in San Diego, so its not really cold either, so I dont think its overly thick oil or something like that.

LifeOnABoard

Nope, never did figure it out. But just for the sake of making sure it's clear, my start performance is only slightly improved after it's been warmed up. If yours only gives you trouble if it's had time to sit and think about life first you may very well have a weak fuel pump, or the starter could be sucking voltage from it. The 4runner doesn't start to build pressure until it is cranking so this is an issue.

I have another Actron fitting if you want to modify it like I did. Or you can try to get the correct parts from the dealer. It might be worth it to look at the fuel pressure.

BTW, I like the surf trip pics. I used to live in PB but moved up here in 96. This is my local spot, we're lucky to get 6 weeks of good surf every year, ha!

vital22re

iTrader: (2)

Have you ohmed out the cold start temp switch? Or the ecu coolant temp sender?

VANCE164

iTrader: (1)

Yea and also If you want fuel pressure tests that where you hook it up at and when the truck is in the run position the pump should be u can also jump the fuel pump befor you start it and see if that helps at all. My 88 has long starts due to the fact I have my tps unplugged (needs to be readjust and baby had time) so I would defiantly test that and the MAF

BajaRunner

Vital, Do you know where the cold start temp switch is located? Yes, I just ohmed out the ECT temp sensor and it appeared to be spot on.

LifeOnABoard: I was wondering what your name meant, if it had anything to do with surfing, cause I can relate Hey the waves don't look too bad there. My buddy just moved to Maine last year actually! He said the summer time wasn't all that bad with the hurricane swells.

BajaRunner

Bump... Looking for any advice, thanks.

J2F42C

Baja,

It does sound more electical (sensor) than fuel related if it only occurs when cold correct? I hate armchairing problems like this but I'll give you my 2 cents worth.
1. Check both lines from the battery to make sure both ends are good. My old Ford Bronco's cable from the battery to the starter looked good but after pulling it off the starter some of the copper ends had frayed from the eyelet. Anytime under 40 degrees and it would take it 3 to 5 seconds to turn over. New battery cable and I was good to go.

2. Check the cam and crank sensors along with their connectors.

BajaRunner

Thanks. Any experience, advice, whatever is appreciated. I've never had a problem like this and am a little uncertain where to start. :/

Ill hopefully get to try this in the coming days.

fishingorwishing

I think I'm having the exact same problem as you. Really frustrating, to make matters worse this happened after a rebuild. That magnifies the possibilities. I have 243,000 on this truck original fuel pump. So of course my first thought was fuel pressure. This may help everyone too B&M make a pressure gauge for civics its designed to attach after the fuel filter. Its the exact same thread size as on the end of the fuel rail. You have too cut a notch in the tb cover and add a 2 1/2" brass pipe to it but works perfectly. Don't have the model # but can go look it up if anyone is interested. ok back to my problem. I tested fuel pressure, fuel pump doesn't turn on till engine is cranked, like several said has to get signals from cps sensors. But as soon as I crank it over it shots to 43 psi in a split second even after its cooled down. I read that that whole pressure drop when you pull the hose from fpr. This supposedly came from Gadget also he said pressure should be at 42-43 psi period. As far as it bleeding off over night, the fuel pressure test states its supposed to bleed off but its suppossed to hold I think 28 psi for five mins. mine bleed off to about 11 psi, but passes the five minute test. Does that mean its a bad pump? I'm thinking my case it may be the IAC valve. I think its not closing/opening like it should when cold. I've replaced ECT sensor, MAF sensor and fpr sensor, was going to try a ecm but after hearing whats going on with yours I'm not sure thats it.

When did this start with yours? Did it start all a sudden or gradually got worse?

fishingorwishing

Not sure this motor has a cold start temp switch. Cold start injector? I know it doesn't have one of those.

brian2sun

Batteries loose charge when they're cold and an older battery looses more charge. Mine has always taken a second or 2 longer to start in the winter, sometimes longer when it's snowing or really freezing. A new deep cycle battery with a high CCA will probably take care of your issue.

J2F42C

That is why I was thinking that Baja should check the battery cable(s) and each termination.

If memory serves me well, I think he bought a new battery, but could be wrong.

As a T4R board lurker from time to time, I did see where one member had to replace his fuel pump because it died. I wonder if it was a gradual death, or one day it just did not want to turn over. That is why if Baja could test fuel pressure after sitting overnight, then once again in a latter part during the day but not with the engine dead cold and check the readings vs. those in the FSM. If the problem isn't fuel related, he moves on. I wish the 5VZ fuel rail had a schrader valve for a time like this.

fishingorwishing

Can't speak for the op but no way this is the battery. If its cranking over my guess would be its not the battery. Mine sputters for a split second after it starts also.

fishingorwishing

I have read somewhere that fuel pressure is supposed to bleed off over night, like I said with my truck even sitting for a few hours pressure down to 11 psi. I crank it over and fuel pressure shoot up to 43 psi within a second. Does someone have any knowledge on whether pressure is supposed to stay up when letting it sit? or is it supposed to bleed off gradually?

brian2sun

I think he should still check fuel pressure too, but I think it's more likely to be a charge/weak connection thing.

I wouldn't say "no way". Batteries do loose charge when it's cold and a battery with a weak charge (not dead but weak) will take longer to crank before the engine fires up. It runs fine after it starts so if it is a fuel pressure thing, then it's only happening during the priming process. That still could be it, but I'm thinking it's not as likely.