Car stumbles on cold start

[s2cmpugh]

Good day everyone. On a cold start (after the car has been sitting overnight) I have to crank it a bit longer to get it started, but once it catches it stumbles for a bit, then goes to normal high idle. So far I've replaced:

Spark plugs
Fuel filter
Dizzy cap and rotor
Cleaned the IACV
Timing belt
Balance belt
Water pump
Thermostat
Valve adjustment

Any ideas? I'm fairly sure the FITV is working fine since it does go to normal high idle and then comes down. I tested the "starter booster valve" (this is attached to the opposite end of the plenum from where the throttle body is) and it's NOT holding vacume very well.

Any help would be greatly appreciated.

Thanks,
Cris P.

[CB7Dominican]

Well my friend me and you are the same boat because I have the same problem with my cb too...I have made the same changes as u and still have the same problems and the car runs like a baby! After some time I just said fuck it! Andi have had no problems ever since thank god!...but my suggestion to u is just keep ur eye on the car for any funny noises or anything like that for the most part you should be good

[vietkid_2006]

i have to hold it for 2 seconds on a cold start.....

[CB7Dominican]

I have to give my car 3 cranks to get her started in the cold

[s2cmpugh]

Yeah, once I get the car started it runs real good. Even after it sits for four or five hours it starts fine. Just seems to happen after sitting overnight or a couple days.

I'm sure it's something simple....

[HondaFan81]

Did you check your starting system? Make sure your battery and alternator are working properly, get them both tested. A failing battery could cause this problem.

Your battery is critical to providing the properly voltage to all components that make your engine run properly. Your battery could have enough voltage, but not enough cranking amps (esp. if cold starts).

[s2cmpugh]

Did you check your starting system? Make sure your battery and alternator are working properly, get them both tested. A failing battery could cause this problem.

Your battery is critical to providing the properly voltage to all components that make your engine run properly. Your battery could have enough voltage, but not enough cranking amps (esp. if cold starts).

Well the car cranks just fine, cold or hot start. It just stumbles for a second or so once it catches and runs perfect after that.

[HondaFan81]

[QUOTE=s2cmpugh;2232753]Well the car cranks just fine, cold or hot start. It just stumbles for a second or so once it catches and runs perfect after that.[/QUOT

Didn't you say it takes more cranks than normal? It should be a strong crank throughout.

I'd start with getting your battery fully tested. Check battery/alternator connections as well for good condition and contact.

[s2cmpugh]

Well the car cranks just fine, cold or hot start. It just stumbles for a second or so once it catches and runs perfect after that.

Didn't you say it takes more cranks than normal? It should be a strong crank throughout.

I'd start with getting your battery fully tested.

I might have to crank it about 2-3 seconds before it catches, then it stumbles just a second and goes to high idle.

I've got a multimeter at home, can I use that to test the battery?

[HondaFan81]

I might have to crank it about 2-3 seconds before it catches, then it stumbles just a second and goes to high idle.

I've got a multimeter at home, can I use that to test the battery?

It seems your problem occurs more when battery in load, hence a true battery test needed to check if you maintain proper amperage. Take it to an auto parts store, they usually do it for free.

A DMM is good for checking battery voltage, but that's not the whole story here.

[91@CCORD74]

If this helps any, I have a brand new Optima yellow top and still have this problem, after sitting I go to crank my car and it turns over, stumbles, turns over stumbles catches bogs for a couple seconds then its smooth

[HondaFan81]

If this helps any, I have a brand new Optima yellow top and still have this problem, after sitting I go to crank my car and it turns over, stumbles, turns over stumbles catches bogs for a couple seconds then its smooth

By "stumble", do you mean the engine is running at this point?

If so, I'd check for proper TPS setting & function to start with.


Also, what type of engine management do you have?

[91@CCORD74]

By "stumble", do you mean the engine is running at this point?

If so, I'd check for proper TPS setting to start with.


Also, what type of engine management do you have?

yes, the stumble is running but if you hit the gas it bogs down then 4 seconds later its cool, and how do i go about checking the tps??
and stock ecu

[HondaFan81]

I tested the "starter booster valve" (this is attached to the opposite end of the plenum from where the throttle body is) and it's NOT holding vacume very well.

BTW, the air boost/starting valve works by providing another air passage for outside air into engine only when cranking. So it is supposed to remain open when engine is off.

However, once engine is running and therefore develops vacuum the air boost/starting valve is supposed to close.

If it were open after engine is running, you would have a higher than normal idle (unless you compensated for this elsewhere, like idle screw near fully closed, etc).

[s2cmpugh]

BTW, the air boost/starting valve works by providing another air passage for outside air into engine only when cranking. So it is supposed to remain open when engine is off.

However, once engine is running and therefore develops vacuum the air boost/starting valve is supposed to close.

If it were open after engine is running, you would have a higher than normal idle (unless you compensated for this elsewhere, like idle screw near fully closed, etc).

So when I hooked up my MightyVac to the air starting valve, applied vacume with the engine OFF, it should NOT have held vacume?

I don't have to touch the gas on mine..it'll catch itself after about a second, then warm up just fine.