brycetryce

Hi another hard start thread (sorry I know but no other thread has been helpful to me). 3vze runs great at operating temp but on a cold engine I have to hold the gas for it to start (pumping the gas while cranking seems to help it start easier.) Additionally, until the engine has some register-able heat it wont hold idle and I have to dance on the gas to keep it from stalling while in neutral (noticeable misfire while this is happening). Otherwise the idle will slowly drop until it stalls. In gear, i can floor it and it wont rev above 2000 before its warm. As soon as the thermostat shows heat it's like a switch is flipped and the engine holds idle, pulls well. The warmer the engine is the more torque it seems to have and the easier it is to start.

Also I live in southern california so when I say "cold" I mean 65 degrees.

No vacuum leaks, no codes, new fuel pressure regulator, new fuel filter, new fuel pump, distributor cap and rotor, ignition coil, battery, starter, spark plugs re gapped (all plugs were clean), timing is to spec, tps adjusted, clean throttle body, my "IAC" valve inside the TB is clean and working, tested resistance of VAFM, ECT relay, thermo time switch, my cold start injector checks out fine as well. Jumped B+ and FP and tried to start, no change. Egr isn't sticking.

At this point I'm thinking bad or / leaking injectors, , fuel damper?, not enough fuel pressure at startup?, bad vafm?

I'm very limited on tools time and money so any direction to save some steps would be much appreciated. Thanks in advance.

Co_94_PU

iTrader: (-1)

It is starving for air, coldstart has whats called "warm up enrichment" where it adds fuel to decrease warm up times. Pumping the pedal on an efi engine doesn't do anything but open the butterfly valve, on a carburetor you would get an extra bit of fuel that doesn't happen with fuel injection. You might have a clogged air filter, or you more likely misadjusted the throttle linkage while servicing the throttle body, there is a specification I don't recall but make sure it's got a crack/gap atleast.

Probably wouldn't hurt to check the tps adjustment, idle switch. Egr system not stuck open. And the doohickey , sorry long day, that slows down the throttle blade when you let off the throttle.

brycetryce

Thanks for the reply co_94. For some reason I swear pumping the gas helps it catch faster in initial startup (I know I know EFI and all that). Anyway, new air filter, throttle linkage is in spec, tps in spec. Egr valve is working as far as I can tell. Dashpot is fine as well. Even with the throttle wide open I can't put it in gear without a stall until it's warm.

coryc85

What Co_94_PU is trying to tell you is that pressing the gas pedal is not doing what you think it is doing. When you press the gas pedal, you are opening the throttle plate and allowing more air into the engine. I don't have much experience with the 3VZE, but obviously I'd suspect your idle air control valve. Not sure what year you have and whether there is any adjustment, but that valve is responsible for letting the extra air into the system when cold, there are some tests in the FSM for it, so I'd perform those and then go from there.

brycetryce

Thanks for the reply. I'm aware that it shouldn't make a difference but dancing on the pedal while cranking seems to help the car fire more effectively than just keeping the throttle open. Maybe I'm just crazy after dealing with this for so long. I have a pretty erratic idle I'm starting to notice, just in terms of one stoplight to the next I can see the idle speed has changed. My iacv is actually working well. I notice a drop in idle after a warmup and after I'm able to keep the idle steady after the inital start, to me that means the iacv is doing what It should. I've adjusted it a couple times and havent noticed a difference in my hard start issue. The issue seems to be progressing and its becoming harder to start when hot. I have to hold the throttle open to start after just a few minutes of it sitting. Injectors???

wyoming9

iTrader: (1)

Hard Hot starts points toward some leaking injectors if every thing else is good.

What do the plugs look like??

More air at start up would help the plugs to dry faster.

Are you keeping an eye on the oil level ?

brycetryce

Plugs all look good, took em out to re-gap about a week ago. Normal wear. Thinking of changing the plug wires cause I don't if thats ever been done. I keep the oil topped off consistently. Definitely have some seep from the oil pan gasket (one or two drops overnight). Thanks again.

Terrys87

iTrader: (1)

I do not know the 3.0 but basically the electronics is the same as the 22re so I am going by 22 experience. On a 22re, The VAFM will not throw a code unless the cable is not hooked up. Make sure the flapper is moving freely. Get a Haynes manual and run a resistance check per manual on the VAFM. I have only ever replaced one Cold Start Injector, all other cold starting issues was the Cold Start Injector Timing Switch.

Just my opinion on the TPS. I too think on a truck with the original TPS on it, sometimes just barely touching the gas pedal will move the TPS just enough to make it start easier. My pea brain idea on that is that the fingers that slide on the foil tracks inside are so worn down that the computer can not get a good reading as to where the TPS is actually sitting. There are threads on cleaning the contacts inside the TPS and that can help the TPS pass a resistance check on the TPS. I too have cleaned the fingers inside the TPS and got them passing but still had issues. After replacing with a new TPS, I had no further issue on that TPS problem. From now on I replace a TPS with a new Denso.

I can get a 22 motor to start within one revolution of the crankshaft. Things I do in not particular order. Follow the manual.
Adjust valves,
complete tune up using factory parts, parts can be found cheap on line. Dealer is cheap for some tune up parts, plugs, cap, rotor. Wires I get off of ebay. Fuel filter I get from part store.
Intake system cleaned of all carbon including EGR,
Test and clean all sensors, especially the Cold Start Injector Timing Switch,TPS,VAFM,
No Vacuum leaks.
Do a resistance check on your Coil.
If you are suspecting your injectors, there are test you can do on the injectors using a 9 volt battery, syringe, carb cleaner. Google has some test you can do. i have the test on one of my build threads somewhere.

From now on when I have an original TPS and having issues, I will replace it with a new one. Most of these trucks have hundreds of thousands of miles on them and the TPS has been cycled literally millions of times. Look at how many times you are on and off the throttle in a single mile.

Before I really start troubleshooting a truck, I do all of the above. Like you suspect old plug wires. Sometimes a good tune up fixes several issues and dont have you chasing some other issue that is not related.

brycetryce

Thanks for the reply. I have a FSM that Ive used to resistance test the VAFM as well as every sensor I could find. My TPS is less than a year old but ill see if swapping it with another one changes anything. Been working on the breaks recently but when I circle back to the start issue today or this weekend Ill update here and probably will have more questions. Thanks again

wyoming9

iTrader: (1)

I meant if you have leaky injectors the gas is getting in the oil thinning the oil out every day

Gasoline is not a lubricant

brycetryce

Been a while but for anyone curious my problem was bad compression from worn valves. Fixed now.

22BrokeBoyRE

How did you diagnose your problem to come to that conclusion? Also, how did you remedy the worn valves?

brycetryce

Did a compression test results were bad. Pulled the heads, found a new pair already assembled online a swapped those in.