Intermittent hard start

97t4r81

97t4r81

New member
My 98 3.4, is having an issue starting easily sometimes. I'll crank it for 5-6 seconds and stop, then crank again for it to start. Then other times it just starts right up. I've had this issue for about two years and I've tried several things to correct some seemed to help at first, but this issue is still ongoing. I've cleaned maf,throttle body and iac(tested iac for function, the flapper moves when current is applied) new plugs and wires,timing belt/wp and all the pulleys. Fuel pump and filter. These were all needed maintenance items so I wasn't exactly throwing parts at an issue, but I sure hoped it would help. Ive checked spark and moved coils around.I've looked in the radiator cap with it running and saw no bubbles, no fluid loss. I did a compression test and got one cyl that was low, it was my first and I'll retest to compensate for noob error. The truck runs great, no codes, seems to have the same pull as always. Only other thing is my milage has been slipping too, but in a way that could be driving variables. Any ideas, things I've missed?
 
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Does it matter whether the engine is cold or hot?

Two possibilities to consider would be an aging fuel pump or ECU main fuse.
 
It doesn’t matter if the motor is hot or cold, but most mornings it happens. Then randomly during the day. Then some mornings she starts right up. I’ve replaced the fuel pump and filter. I’ll check the ecm fuse, if not blown, what am I checking for?
 
97t4r81 said:
It doesn’t matter if the motor is hot or cold, but most mornings it happens. Then randomly during the day. Then some mornings she starts right up. I’ve replaced the fuel pump and filter. I’ll check the ecm fuse, if not blown, what am I checking for?
Click to expand...

It just may not making contact all the time. Cheap to replace.

Check all grounds and terminals. Clean if need be.

Do you have access to a scanner that reads live data?
 
I checked the ecu fuses none were bad, I’ve gone over the grounds and terminals. I tightened the grounds a tiny bit, thank you Caesar. So far I’ve started it 3 times without a problem.
 
97t4r81 said:
I checked the ecu fuses none were bad, I’ve gone over the grounds and terminals. I tightened the grounds a tiny bit, thank you Caesar. So far I’ve started it 3 times without a problem.
Click to expand...

Good to hear. It may not be a bad idea to go over the ground connectors with some emory cloth or the like though in the desert out there you guys don’t really have to worry about oxidation. :roll:
 
So time for an update and to ask another question. After checking grounds,cleaning terminals, checking ecu fuses, and all the above maintenance , my rig still has a randomish hard start/long crank time. That's the update, now to the question. Could an injector have a failing internal check valve that could drain fuel into cylinder, losing fuel pressure and flooding cylinder? I don't smell gas in the oil. I don't smell fuel in the engine bay(little bit around evap canister).When she does start after a long crank (5-8seconds,2 key tries) episode the motor will just barley be catching(stutter)then it just gets into normal operation rpm, sound and feels strong. Strong smell of exhaust when started, still no cel. Any ideas? Thanks
 
Subscribed... I've had this issue forever and haven't figured it out yet either. Anyone tried a Fuel Pressure Regulator? Perhaps it's losing fuel pressure and needing to get fuel all the way back to the engine?
 
I'm looking into how to test the fuel pressure regulator? Does anyone else have a very strong smelling exhaust?smells like an old Chevy on startup.
 
So this morning had again same long/hard start(6-8 seconds) then she fires, but limps then catches good. We run errands, then I park her for two hours, find same long start, without the limp. Wtmf? Does anyone have fuel pressure regulator test instructions? For perspective I've had several vehicles that were wayyyy harder to bring to life, but this is my dd, exploration rig, and it just drives me mad(anger!) to have this. All my maintenance improvements have helped for a bit(when I did the TB,WP and all belts/bearings, she sprang to life first crank, same with fuel pump, then after a few days, we're back to the same crap shoot. I feel like I'm missing some silly beginner mistake(it does have a full tank fuel and oil). Smiles. Either really easy or oh shiiiiitttttt!!!!!!!!
 
My guess is the check valve in the fuel pump is allowing the lines to drain while sitting. Try turning they key on but don't crank the starter. Wait 10 seconds with the key in the on position and then crank the engine over. Does it fire right up every time? If so, that 10 seconds is priming the fuel rail and you have your answer.
 
2016 4Runner SR5 said:
My guess is the check valve in the fuel pump is allowing the lines to drain while sitting. Try turning they key on but don't crank the starter. Wait 10 seconds with the key in the on position and then crank the engine over. Does it fire right up every time? If so, that 10 seconds is priming the fuel rail and you have your answer.
Click to expand...

I've tried that, replaced the the fuel pump as well as installing an all brass check valve from the local hot rod shop inline on the fuel line on soft line drive side on side of intake plenum. It almost seems like the angle that the rig is parked on makes a difference, nose up seems to work better than nose down(not scientific)and which side it leans. I'm going to buy a jump starter, the newer small ones, in case this issue erupts into a no start. Also going Monday to interstate to have them check battery and replace if needed.
 
97t4r81 said:
I've tried that, replaced the the fuel pump as well as installing an all brass check valve from the local hot rod shop inline on the fuel line on soft line drive side on side of intake plenum. It almost seems like the angle that the rig is parked on makes a difference, nose up seems to work better than nose down(not scientific)and which side it leans. I'm going to buy a jump starter, the newer small ones, in case this issue erupts into a no start. Also going Monday to interstate to have them check battery and replace if needed.
Click to expand...

Different vehicle but I had a 95 Cherokee that would do something like this and it turned out to be the fuel pump relay. It finally left me stranded, I swapped the relay with the AC relay and it fired right up. Those are really the only 2 suggestions I have just from personal experience. Hope you get this figured out!
 
Two separate things. First I would replace the front O2 sensor, I do not think it is the cause of the hard starts but it is the last part of your tuneup and it might help with the mpg slippage. As for the long starts, because of the limp when starting I would think fuel, but because of the randomness of it I think it is an electrical problem. Since you have dealt with most of the main culprits I would suggest upgrading your ground from the battery to the engine block and making sure the one from the block to the firewall is in good shape. I have had long start issues before in my tacoma and old pu Both times they were ground issues. The 86 pickup was a ground fault to the ecu and the tacoma needed the extra ground to help with the starting. My theory (and I am going to ignore the eyerolls) is that the starter motor maxes out the ground and everything else that needs ground while starting (ecu, fuel pump etc) does not get the ground it needs to function properly. On my tacoma I replaced the original ground terminal end with an old fashioned lead one with a post and ran a #2 wire to the frame below and from there to the engine block. I left all the other grounds as they were. I followed a writeup I found on a tacoma forum. This makes a second pathway for the ground while starting and cut my starting time to just a couple seconds. This may not fix your problem but for maybe 30$ and an hour of your time it will not hurt
 
That stinks. I was hoping it was a loose connection or the like for you.

If you believe it is fuel related, buy a gauge and test.
 
Hard start intermittent

My truck also does this but only intermittently when it’s warm.

I have a new fuel pump but also believe it’s fuel related. I’m going to test for fuel pressure bleed down when it’s hot and not running.

I’m suspecting a injector....

Again very intermittent.

Look around the hot rod web sites for the correct banjo fitting to add to the fuel rail.

You can then do a mechanical gauge or electronic sending unit. I would opt for the latter unless it’s temporary.
 
So to update this thread y’all, I kept having the long/hard start after going through the battery, grounds,new fuel pump,iac/tb clean, maf clean and new plugs and wires. So the other day it won’t start, nada. I mess around with the key a few times and get the famous “click click “, first time for that. So I changed out the starter and that seems to have solved my issue(knock wood). After removing old starter I found the contacts in bad shape. So to those with similar issues check the starter contacts, even if you don’t have the click click sound yet. Hope this is helpful
 
Probably. I put my old one that I only have 25-30k miles on rebuild. I’ll order th the kit in another decade
 
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