Difficult to start

Hello everyone!

Never thought I'd join a forum, but I really like my truck and want to keep her going as long as possible. Hopefully, this post is going in the right spot.

I have a RWD '97 Taco with the 3.4L V6 5-speed manual

I bought the truck at 161k miles and have used her as my daily driver all the way to her current 263k.

The previous owner had her lowered 2", added a K&N cold air intake, a Borla exhaust (which is at least from the cat back for sure) and a short shifter because he didn't like how long the throw was for the stick.

The only thing I've added is an AirRaid throttle body spacer as far as modifications go. I'm super new to anything related to cars so I probably got taken for a ride on the AirRaid part (according to some internet reading, haha).

Recently, she started to have issues starting (would take anywhere from 2 - 6 attempts before she would start and at her worst, I had to pump the gas) and so began my journey learning about this truck.

So far I've:

Replaced the starter (it died)
Replaced the coil pack and wires for the spark plugs

Replaced the upper and lower plenum gaskets (I had a bad fuel leak in the lower that sits on the intake manifold)

Had the fuel injectors cleaned/fixed by Dr. Injector (a highly recommended injector guy here in Washington state) - so many issues with the injector, if you PM me I can fill in more of the story on why there aren't just new injectors in the truck

Replaced all the belts except the timing (when I looked at the timing belt it looked brand new so I left it alone, which also means I didn't replace the water pump)

Replaced the battery with a big ol yellow battery (forgot the brand) thats supposed to be amazing

Replaced the fuel pump
Replaced the fuel filter
Replaced the fuel pressure regulator
Cleaned the Air filter and MAF
Replaced the spark plugs (NGK silvers)
Replaced clutch, flywheel, pressure plate, rear main seal

It's better than before but it still takes anywhere from 2 - 3 times to start the truck up.

I used to get about 320 miles on one full tank regularly (ran out of gas on the freeway at 325 once just because I wanted to see how far I could go haha)

Now I get about 280. The only thing I've done that might have affected the MPG is the throttle body spacer (but I'm not really sure if it would drop it from over 300 on a tank to 280, but again, I'm new to fixing vehicles)

I was getting a P0172 code from my code reader, but I unhooked the battery when I replaced the fuel pressure regulator (today as I post this) so I'm not sure when or if that will show up. But, I let the truck cool down for about 3-4 hours and went to start it again and it took two times to get it started.

I'm at a loss as to what to try next to fix the difficult starting.

Any help or advice on a next step would be awesome.

 

You get a flow rate sheet or summary of how your injectors performed?

P0172 is for a rich state, and I assume your vehicle is hard to start when warm/hot right?

Starts up better as a cold start?

 

Yes, I did get a flow rate sheet and it had said that they were all dirty basically and the spray patterns were being affected. 1 injector was shot and he sold me a new core from his stock (which matched the oem part which was nice). Unfortunately, I no longer have that sheet. I finished reinstalling the injectors about a week ago and so I threw out the sheet once I was happy the leaking fuel issue was fixed. But, the hard starting still occurs. So I did the next thing on the list of possible issues which was replaced the fuel filter and then yesterday I replaced the fuel pressure regulator.

This morning, I will say though, showed me that maybe I jumped the gun here. It started up fort try, no problems. Hopefully, it continues that way! I was just discouraged when I tried yesterday (after letting it cool down for about 4 hours) that it took 2 tries to start it.

To answer your question though, it's hard to start cold. Once it's warmed up, it fires up right away. But if it sits overnight, the next morning, it takes a few tries to start her up. The code said "System too rich Bank 1".

Thank you again for your reaponses!

 

Not sure if you've accounted for this yet but I had an issue exactly like yours, my buddy who's a Toyota tech told me the purge valve is probably stuck open. Got an aftermarket Dorman one online and haven't had a problem since.

You can check if yours is working by:
1. Disconnecting the electrical connector AND one of the two vacuum lines that lead to the fuel tank from the valve, just trace the line, one should go to your engine and one should lead to the back of the engine bay, the second line is the one you want to disconnect..
2. Start the truck.
3. Put a wet finger on the hole of the valve you just disconnected, if it is working as intended you should nothing, if it is stuck open you should feel a vacuum.


The purge valve is supposed to open at a specific time and allow excess fuel vapors in your tank to burn while the engine is running. Your problem is that it is stuck open and so when your truck sits for a while, the fuel vapors from your tank make its way into your engine and flood it, causing very rich condition and a hard start.


Location should be near the brake master cylinder right above the fuse box and look like this. You should see an electrical connector and two vacuum lines connected to it


** I see you don't have the problem anymore, my truck started starting normally too but I replaced my purge valve anyway since it did stick open at some point and was the original part. If I were you I'd leave it alone for now and if it happens again, try testing your purge valve. Probably better not to throw parts at it anymore since it seems like you've done pretty much everything. **

 

Thanks for your response! If I still have a hard time starting it I will look into this next! You're the first person to educate me on this so I'm super grateful i'll have another path to take if needed!

Thanks again for your super informed response!

 

With the age of the truck and what you have replaced. Try replacing the Circuit Opening Relay, (fuel pump relay). Replace a few of these before. It sends power to pump and some other places I cant remember. It should be located left side lower sterring column. After relay heats up, makes contaqct better then when cold.

 

Well, the problem persists, but I am going to try your suggestion regarding the purge valve. I don't know why I didn't join the forum sooner. Everyone has been awesome here!

Thank you all!

 

I'll try this next. I replaced the purge valve and the solenoid, but it's still having trouble. Auto parts guy said I might have to replace the evap canister...?

 

The evap canister should not cause a no start condition. It would make it hard to put fuel in tank if clogged up. The purge vale could cause a code for running rich if it is stuck open and drawing fumes from tank when not supposed to. Will cause a hard start after filling with gas. If you are having a hard start after it has been sitting for awhile, try listening for the fuel pump running while someone is cranking the engine. May be hard to hear. My money is on the relay. After cranking a few times the relay heats up and makes contact and sends power to the pump. After the relay heats up, can work for a long time till cools down again. A few hours of sitting. Find and try tapping on relay when not starting. Should feel it click while cranking. Good Luck

 

Coolant temp sensor may be out of range. That's the first sensor the pcm looks at on startup

But you should also get a inline spark checker and fuel pressure gauge on it to see if spark or fuel is missing when it cranks but won't start

 

Update:

So, I replaced the COR and it didn't solve the issue, however I noticed a cracked vacuum hose that sits on the upper plenum that I've never removed in all of my fixing. It goes from the upper plenum to the purge valve. I've replaced it and hopefully, tomorrow it will start right up.

Fingers crossed anyway.

 

I honestly doubt a vacuum leak would cause a problem to THAT magnitude in your truck, but it's good to replace your lines if they're rotten so you did fine on changing it. I honestly think what that guy said about your fuel pump relay might be a good lead, it seems like a problem with air or fuel delivery.

 

I believe the Circuit Opening Relay is the relay for the fuel pump...? I could be wrong. I didn't see anything specifically labeled for the fuel pump in any diagrams for this truck. If there is a relay I'm not seeing, let me know!

I replaced the COR yesterday, but it didn't seem to solve the issue.

 

@Siege. I had problems with my old engine with leaky injectors. Whenever I did an oil change things would get better. Seems like the gas would leak through the pistons into the oil and the PCV (Positive Crank Vent) would recycle the gas vapors back in to the intake and the Computer would keep trying to pull fuel away, but could never keep up. Thoughts anybody?

I got my Tacoma without knowing n e thing about cars/trucks. Keep up the research and fixes won't seem so daunting. Sometimes they throw you for a loop though. This is an awesome website for inspiration or at your wits end.

 

That happens occasionally. Classic sign of a leaky injector..

On diesels you can look to see if the oil level goes up over full