The Case of the Intermittent No Start

Bought a 2006 TRD OR 6 speed in June of 2023 with 166k miles. Had weird throttle/power bogging down issue right around 3000 rpm, like it was a hiccup then continue on through the rev range. New spark plugs, new denso coil packs, new denso MAF, new OEM fuel pump assembly. Kind of took care of that mid rpm power delivery problem, but for some reason my truck started having hot start issues.

Truck starts fine when cold, but if I left it in a parking lot for over 5 minutes after reaching operating temperatures, the thing wouldn't start half the time. It would crank and crank but no ignition. No check engine lights, battery is from 2022, everything SHOULD be working correctly. I would pop the hood, let the engine cool and unhook the battery, that would somehow let it start back up, but sometimes it would take up to 15 minutes waiting. This is INTERMITTENT, so sometimes it starts no problem when hot, sometimes when you're in a hurry it decides to act a fool and no start.

Searching through the forums I decided my next thing to check is leaking injectors. Thought to myself that maybe an injector is leaking and flooding the engine, making it difficult to start when hot. Found some re-manufactured oem denso units from Motorwest Performance. Got the "new" ones installed last week and have not had a hot start issue since! I am still worried that it was something else and I just have not met all the correct conditions for that hot soak no start to occur again. For now, it all seems like it worked according to plan.

When I removed the throttle body, and more so the intake plenum, I got a real big whiff of gasoline. Was unsure if that's how it it supposed to smell... But I thought to myself "that might be a leaky injector".

Anyway, thank you for listening to my rant, just wondering if you guys had any thoughts on what it might have been or still is. Still dealing with that ~3000rpm power bog sometimes, but it's hard to notice.

Threw some pics in from the day I bought it to, found some newer TRD wheels and suspension, then my cross country road trip from ID to NJ. The truck was definitely ridden hard and put away wet prior to my purchase, however it's been fun to tinker and fix it as I go along. Sold a brand new Ford Maverick to get back into a Toyota, I have way more fun bangin through gears on this anyway.

 

I don't think the Injectors were the issue.
Almost sounds like a fuel pump power issue.
The truck starts on Hi-speed and then goes to low speed.
Same thing happens when you hit higher RPM.

Maybe the fuel pump relay.

But who knows, Run it and see what happens

 

I'm thinking you may have a fuel pump relay that has flaky contacts, the truck starts in high speed and switches to low speed after a few seconds and it also switches to high speed at higher engine speeds and loads.

If the high speed contacts in the relay are bad it could exhibit the symptoms you describe.

You could swap it with the DIM relay and see what happens.

 

I swear if it comes down to being the fuel pump relay, I am going to feel pretty dumb for not coming here sooner! I'll swap it with the DIM relay to see if that helps. Appreciate the ideas.

 

Wiring diagram for reference.

 

Don't worry dude, i went through a similar issue. Turned out my problem was the effing Key...

 

I thought that might be it as well, but my security light goes off when I insert both my keys, which makes me think they're not the culprit. Was your problem resolved with a new key?

 

My problem was the aftermarket key that came with the used truck that i had been using for a decade.

The key finally shit out. It was intermittent for a few months which sent me on the fuel system parts cannon escapade.

A proper factory key finally fixed the issue.

My security flashy light never worked the whole time, i didn't even know it was there until i did an obd jump reset.

 

Alright, so I threw in a new relay from auto zone, have a Toyota one on order. Drove around a bunch today running errands, going into places for 10-15 minutes which is the perfect amount of time for the engine to no start. It fired up every time RIGHT away. No long crank, no hiccups.

In some other threads I was reading about the fuel pump resistor. Do those fail or start to go bad at times? Could that cause the mid rpm range power drop? It's such a small loss of power I'm not sure I even want to chase the problem, but it's so weird how it's only at around 2800ish RPM.

Thanks for all the help, I appreciate it.

Fisha, good info on the factory key. Might need to get a new one made up here soon to mitigate that issue.

 

I had a similar intermittent no crank no start issue. Every Saturday morning it would start after sitting Monday through Friday. After that sometimes it wouldn’t crank. Trying to figure out what situation would cause it drove me crazy. Hot but not too hot, almost completely cold but not fully cold, moon phase, I did or didn’t cut my finger nails.

My problems ended up being the starter solenoid contacts, the clutch pedal switch, and possibly the clutch pedal switch relay which I bypassed. I also threw the parts cannon at the fuel pump resistor which made no change.

 

They can fail.
When they do, the truck typically dies about 3-5 seconds after start up.
In your case, you were having a "high speed" symptom issue. The relay controls High Speed.

 

Roger that, it's all starting to make sense to me the more I read about the 1gr-fe. Thanks so much for the help, I'm gonna see how the relay works. Hope that solved the problem, but I will report back here if not.

 

Just over a week of no issues, only to be hit with a typical crank/no start after reaching operating temps then going into a store for 10 minutes. Decided to pull the fuel pump relay and circuit opening relay to see if they weren't making good contact. A few more attempts and the truck started back up.

Could the circuit opening relay be going bad and fail when hot? This little electrical gremlin is taunting me.

I was thinking of checking my fuel pressure, but I am unsure of what connectors to buy to hook into the Toyota system. Would like to see if I'm losing pressure over time or something.

 

It's possible, easy enough to swap it with a less critical relay.

You may also want to check connector IB1 Pin 8 (Black/Red) behind the driver's side kick panel and make sure it's not burnt.

You need something like this, you can connect it where the fuel line goes from the frame to the engine.

$31 BETOOLL Fuel Pressure Test Kit 0-100PSI with 9.497.896.30 Fuel Line Fittings

https://www.amazon.com/BETOOLL-Fuel-Pressure-0-100PSI-Fittings/dp/B07LF26ZTJ?

 

Ordered that pressure tester kit, I'll swap out the fog relay with the c/opn relay today and see how that goes. I read about that burnt out pin in another thread, I'll pop the kick panel off today and take a look. Thanks for all the help!

 

Been installing flooring in my house so haven't had time to goof around with the Taco. Something hit me while I was sitting on the couch. If I'm remembering correctly, all of these no start problems started AFTER I replaced the fuel pump assembly. I used an OEM assembly, was costly but was trying to fix the mid rpm power drop. Could I have messed up something during the install? I pulled the bed to do it, so I had a look at everything while it was off.

 

Tested fuel pressure. Showing about 65psi, which based off my small amount of research seems very high. I let the truck get to operating temps and still above 60psi. Turned off engine, let it sit for 15 minutes to see if there was a significant pressure drop but it remained above 60.

Pressure regulator on the way out? This is a new OEM pump assembly installed August of 2023.

 

Maybe a dumb idea, but does that model have a FPR VSV? If it's not opening, that can cause warm start issues.

 

If you mean this little guy? I actually have a new one of those I was going to install, it's sitting in my shed. The parts cannon is loaded, ready to fire haha.

 

2nd gens don't have a VSV for the regulator, they use a 2 speed fuel pump.

That valve is for the ACIS (intake manifold runner control) it won't affect starting.