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Car starts easy when cold or hot, but hard to start when warm.


05pearl

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My car used to start right up - until my last tune. This tune was for the addition of an AVO intake and 850cc DW injectors.

 

The car starts right up when cold. And, if I am away for up to 30 minutes or so, it will also start right up. But, if the car has been off for about 2-3 hours and the engine is neither cold nor hot, then I have to crank like crazy before the car starts. And, the start is rough as it does not fire right up, but has to be continually cranked until I know the engine will not bog down and die.

 

It is possible that when running E85 I did not have this problem (I don't recall for sure:redface:). But, it is definitely a problem when running the 91 octane map.

 

I assume this is a tuning issue? If so, what needs to be looked at in the tune?

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one step colder ngk

Just as I suspected, that is most likely your problem. E85 is harder to ignite and the colder range plugs only make it even more difficult. When compelety cold there are startup enrichments and a high idle speed for it not to be a problem. With the engine hot this really isn't a problem, however when it is warm to the extent where no enrichment is applied you will see a momentary rough idle for about the first 15 secs. I get the same behavior, you can remedy this by just applying a bit of gas after it fires up.

 

As far as it taking some time to fire after the intial key turn, what are the ambient temps?

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Just as I suspected, that is most likely your problem. E85 is harder to ignite and the colder range plugs only make it even more difficult. When compelety cold there are startup enrichments and a high idle speed for it not to be a problem. With the engine hot this really isn't a problem, however when it is warm to the extent where no enrichment is applied you will see a momentary rough idle for about the first 15 secs. I get the same behavior, you can remedy this by just applying a bit of gas after it fires up.

 

As far as it taking some time to fire after the intial key turn, what are the ambient temps?

 

It is happening right now w/ 91 octane. Strange that it never happend before when I was running 740cc DWs and stock intake (now turned for 850cc DWs and AVO intake). Ambient temps have ranged from 70F down to 20F. At 70F it takes about 2-3 hours to see the "hard start / warm engine". At 20F it takes about 1/2 - 1hr to see the hard start as the engine goes from hot to warm faster.

 

Understood about applying gas after fire up, and I have been doing that. The bigger problem is that is can take 5-10 seconds of cranking before the engine starts up in this "warm" state, and I am afraid of burning out the starter prematurely.

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Hmm if it is happening on petrol as well, you might want to inspect you FP. Seems you might be experiencing a drop in fuel pressure. It doesn't really sound like a tuning issue.

 

If it is the fuel pump, why would it fire up right away when cold or hot?

 

Someone mentioned to me it may be the trims? Does that sound like it could cause this issue when the engine is warm? Also note, that this particular 91 octane tune was mapped right after an initial E85 tune - i.e. the 91 octane map started with a base E85 map. I was wondering if there were some minor settings in the E85 tune that may have been left over in the 91 octane tune that could lead to such an issue?

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Well to adjust for E85 from a fueling standpoint all you really do is modify the scaler. Everything else would be the same in comparison to pump gas.

 

I think it could be the pump for the same reasons mentioned above about cold start fueling and such. Also when I say pump, not the unit itself but possibly a bad/leaky O ring.

 

The only way I can see this being a tuning issue is if only after the most recent changes did you experience these problems, immediately after not something that developed over time. If that is the case definately contact your tuner, since you are Ecutek'd there may be som difficulties viewing the problem. Although I in the past have been able to log Ecutek'd vehicles with a tactrix cable as well.

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Ck your fuel pump rest pressure.

 

Do I just log to do this? This is the pressure when the key is in the ACC position? I believe I still have this issue when I leave the key in the ACC position, let the dials go through full sweep, and then start the car.

 

I thought the FP is at 100% when starting the car at any temp - cold, warm, or hot, no?

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