Cold Start Issue (1 Viewer)
- Thread starter LXMUTT
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- Thread starter
- #22
It did have this issue before cleaning. but only when the temp rapidly change of night
Guys does a car still run fine even with a bad maf sensor or there are always symptoms like idle etc.Had issues at cold start low idle and would sometimes die unless I rev it cleaned throttle body and maf sensor made a huge difference.
2001LC
SILVER Star
The numbers do look better. But still LT FT to far off 0 at idle.
I like replacing all 8 plug if I replace any. Coils are a bit pricey, but I've had very good results replace all 8 with Denso. Coil boot kits are second choice and wroth it if any cracking boots.
Bad gas, MAF, clogged "fuel injector", bad plugs, coils or boots, vacuum leaks, weak current from battery, oxidation in wiring, etc. all make a deference. Getting all back as close to factory is the goal for running optimal.
If all good a can of 44K in two tanks with 20 gallon of gas in a row. Use Chevron top grade or a bottle of Chevron Techron in gas. Some Seafoam fogger may also be nice after. After make sure good oil and filter. Get on HWY and run engine at 4,500+ RPM for 5 to 7 minutes (burn-out) heating cylinders and CATS to clean out.
But I don't get to hung-up on these 2UZ when cold. It does give indications of health of components, but they're designed to run at 190F -+.
- Thread starter
- #25
So just to update this I added a new MAF last week while waiting for some new hoses, PCV valve, and rubber grommet.
These to readings are with new MAF and reset computer. It was fluctuating between the two.
Then today I added new hoses, PCV, and grommet and reset the computer.
This is what its at now
.
How do these new numbers look?
No clue if this was the cause of my cold start issues, and I won't know for a while sense its no longer cold in Kansas.
These to readings are with new MAF and reset computer. It was fluctuating between the two.
Then today I added new hoses, PCV, and grommet and reset the computer.
This is what its at now
.
How do these new numbers look?
No clue if this was the cause of my cold start issues, and I won't know for a while sense its no longer cold in Kansas.
2001LC
SILVER Star
Those number look so much better.
I’m going piggyback off this thread instead of starting a new one since it’s a similar issue.
I have tab after tabs loaded up on my iPad and computer trying to figure out my cold start issue. ‘99 with 330k. It runs beautifully when it’s started. Will start with no issues after I initially get it going throughout the day. The moment I park it for the night it won’t Start the next morning. It’ll crank all day long.
New battery, new plugs, new pump, new 20a efi fuse (tried 30a as well), and a EFI Relay on the way. Should get it tues. This shouldn’t be a immobilizer issue since the security light goes out when key is inserted. MAF has been cleaned as precautionary as I read a few no-start thread regarding that. No codes in techstream. I can manually turn on the fuel pump in TS and hear it run. I visually see the damper screw rise with the pump on. The last morning I went into techstream to try and prime the system by turning on the pump before start with no luck.
Any ideas? Is this a fuel pressure regulator? Other common ideas that have come up in related issues is the CPS, leaky injectors, etc.
I have tab after tabs loaded up on my iPad and computer trying to figure out my cold start issue. ‘99 with 330k. It runs beautifully when it’s started. Will start with no issues after I initially get it going throughout the day. The moment I park it for the night it won’t Start the next morning. It’ll crank all day long.
New battery, new plugs, new pump, new 20a efi fuse (tried 30a as well), and a EFI Relay on the way. Should get it tues. This shouldn’t be a immobilizer issue since the security light goes out when key is inserted. MAF has been cleaned as precautionary as I read a few no-start thread regarding that. No codes in techstream. I can manually turn on the fuel pump in TS and hear it run. I visually see the damper screw rise with the pump on. The last morning I went into techstream to try and prime the system by turning on the pump before start with no luck.
Any ideas? Is this a fuel pressure regulator? Other common ideas that have come up in related issues is the CPS, leaky injectors, etc.
2001LC
SILVER Star
CPS?
Use the FSM test for:
FPR, & spark plugs
Leaky FI usually just result in longer crank time until starts.
Check that spark plug are firing, next time by pulling a spark plug and cranking while holding coil attach to plug. Make sure to pull EFI fuse first.
Use the FSM test for:
FPR, & spark plugs
Leaky FI usually just result in longer crank time until starts.
Check that spark plug are firing, next time by pulling a spark plug and cranking while holding coil attach to plug. Make sure to pull EFI fuse first.
Crank position sensor.
I’m thinking my spark plugs are firing. Once I get it started it runs great. The rest of the day I can start my LC with no issues. It’s just when I let it sit overnight or for a long period of time it struggles.
I’ll review the procedure for the regulator.
@900exdriver did you ever figure out what the issue was for you?
Riving this thread to see if you found the issue. I am having the exact same issue and would appreciate insights into what finally helped you. Thanks!
2001LC
SILVER Star
A proper tune-up corrects a lot vibration issues.
Make sure no vacuum leaks
Also all spark plugs good, also tight.
Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! - https://forum.ih8mud.com/threads/ticking-time-bomb-tick-tick-tick-spark-plugs-alert-alert-alert.1045750/
Cold start issues/misfire until warm-up, with complete or some improvement after warm-up. Points to fuel injector, fuel pressure regulator & MAF. Cold fuel injectors run engine rich (more fuel than ait mix). If one or more not working as it should, wherein less fuel spray into cylinder(s). We get a lean condition. Once engine reaches op-temp (ECT 176F). ECM takes-over fuel trims. If we see then see long term fuel trim (LTFT) above 5%, this may point to one or more bad fuel injectors.
In one I'm helping with now. We found spark good, no vacuum leaks but LTFT BK1 15% (HWY level ground holding RPM & MPH steady). It has a P0303. Disconnecting #3 FI, no change in idle. Were having BK1 ( cyl 1,3,5,& 7) injectors cleaned, tested and rebuilt by FIS (Chuck).
forum.ih8mud.com
I've also seen where a bad coil will act much the same. But the one I saw this on, only cold start. Had aftermarket coil.
Most bad coils, that aren't setting off a P030*. Can be seen "misfire" under load.
Some 98-99, had bad throttle bodies.
Make sure no vacuum leaks
Also all spark plugs good, also tight.
Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert! - https://forum.ih8mud.com/threads/ticking-time-bomb-tick-tick-tick-spark-plugs-alert-alert-alert.1045750/
Cold start issues/misfire until warm-up, with complete or some improvement after warm-up. Points to fuel injector, fuel pressure regulator & MAF. Cold fuel injectors run engine rich (more fuel than ait mix). If one or more not working as it should, wherein less fuel spray into cylinder(s). We get a lean condition. Once engine reaches op-temp (ECT 176F). ECM takes-over fuel trims. If we see then see long term fuel trim (LTFT) above 5%, this may point to one or more bad fuel injectors.
In one I'm helping with now. We found spark good, no vacuum leaks but LTFT BK1 15% (HWY level ground holding RPM & MPH steady). It has a P0303. Disconnecting #3 FI, no change in idle. Were having BK1 ( cyl 1,3,5,& 7) injectors cleaned, tested and rebuilt by FIS (Chuck).
When to Clean or Replace fuel injectors
Please post your experiences and thoughts on the subject. I’ve been considering cleaning or even replacing all 8 fuel injectors, is this wasting time and money. I understand keeping fuel injector clean by adding a can of additive to the gas tank, now & then, is a good practice. This keeps them...
forum.ih8mud.com
I've also seen where a bad coil will act much the same. But the one I saw this on, only cold start. Had aftermarket coil.
Most bad coils, that aren't setting off a P030*. Can be seen "misfire" under load.
Some 98-99, had bad throttle bodies.
Thank you! I put some Lucas fuel injection cleaner in and filled up the tank. Starts like it should now! phew!
