Welcome to the forums!

It's possible yer throttle body is worn on the throttle body butterfly shaft. Some have been able to use a shim/washer to realign the shaft and reseal the vacuum leak. Others have replaced the throttle body.

http://www.ttora.com/forum/2-early-tacoma-tech/199779-5vz-fe-high-idle-rpm-pulsating.html[/QUOTE]

As far as the non-start issue goes, there have been many threads on other forums with many others trying to resolve this issue. Many have replaced multiple components with no resolve. Things that have been replaced have been fuel pumps, fuel filters, ECUs, relays, MAFs, TPS, engine coolant temperature sensors, cam position sensors, crankshaft position sensors, FPRs, O2 sensors, IAC valves, charcoal canisters, vacuum lines, starters, batteries, fuel injectors, ignitor units, ignition switches, fuses, gaskets, etc. I'm sure I've missed a few items that others have replaced. They have also tried various cleaners to try to clean the fuel system.

Yes, the IAT sensor is embedded in the MAF as one complete unit fer the 5vzfe and can't be separated apart..

I have the same issue like the others with my 1998 T-100 with the 5vzfe engine about not being able to immediately start the engine after a few seconds of cranking the starter. This can happen whether the truck has been running previously or sitting in the sun all day. When that happens, I usually step on gas pedal full throttle before cranking on the starter again and the engine will usually fire up after about 10-30 seconds or so of cranking. I have tried cleaning my combustion chambers using 2 liters of metered water at a time with pretty good results on cleaning the combustion chamber but the non-start issue will crop up now and then. I have also tried cleaning the injector grounds and fastening bolt located on the air plenum near the diagnostic connector with no effect. I need to try hooking up a separate direct ground from the battery to that ground point and see if it will do anything.

I want to build and install a simple diagnostic harness to all the relevant compenents to check to see if they are gitting the correct power and when they are gitting the correct power when the non-start issue happens to rule out the various components. Tempting to install an electronic fuel pressure gauge to rule out the fuel rail as well. I do it happens to a lot of the older vehicles that have a lot of miles/years on them. It always seems to be a component that is heat stressed/related.

 

Howdy Paulie,

I'm in the same boat. My idle is sticking around 1800 rpm and I'm gonna find out why. At this point I'm so frustrated my blood pressure is stuck at about 1800 rpm also.

Well anyway, Welcome to the T100 Forums.

 

Thanks Guys. Misery loves company I guess. Maybe this is nature's way of telling me to dump this car.

What would a pro mechanic do if I brought this into the dealer for resolution?

 

Recommend a ton of stuff to be done (diagnostics fee plus R&R of lots of parts) with no resolution after you fork out a ton of cash.

 

I would personally pull the throttle body and see if there is a gap on the butterfly valve/shaft and the throttle body. During the vacuum leak test, did you test the area near the throttle body? You can go out and buy a can of starter fluid or carb cleaner which is safer (about $4) and test spray the throttle body shaft area (be careful since starter fluid/ether is highly flammable) in short spurts while the engine is running and see if the engine revs up or not. If it does, you've located one of the possible areas.

 

^^^^^^ This.
It is recommended to use propane bottle or carb cleaner, as the last resort. propane is safe to use. Solvents sprayed around on running engine can cause fire. No big deal to install length of hose onto propane bottle and give shots of gas tracing air leak. As it's likely air leak, should idle control valve be ruled out as possible cause.

 

OK looks like I struck paydirt.

Thought I'd yank the ECT Sensor since its fairly cheap to replace and one of my problems is all about not starting when the engine is hot. I would also note here that the coolant temp gauge was absolutely normal throughout this trouble. So I pulled the top of the timing belt cover, the disconnected the fuel injection rails(the jumper tube that connects the two rails at the front(17mm wrench). Be careful with the two washers on each side. Spent $42 at Napa for the new NAPA Echlin ECT sensor and a 19mm deep socket to operate on it. Put it all back together and voila! Once it warmed up it settled in to a solid 1000-ish idle. I let it idle with the AC running to get it nice and hot, let it sit for 10 minutes and it started right up. Did this several times this afternoon and it always started up and always settled on a 1000 RPM idle.

Be careful in there, anything on top of the engine that's plastic, is brittle as hell... and very likely cannot be ordered as a replacement part.

I'm calling this thing done, solved:clap::clap:. Thank you all for your input on my problem.

BTW I did check the throttle shaft slop (maybe I've got a 64th) and it evidently was not the problem with my machine.

Thanks again guys!

 

OOo...this guy Paulie, I tell ya.....

Shows up and fixes his own problem in 5 post. The nerve of some people.!