[m[ohio]]

I've been searching for a few hours now both here and on DSMTuners and have found no real solid answers on what is causing my hard start problem on my 2G. When it's cold out out the car will usually start right up on the first try, but when the car was run recently or when it's really warm outside it cranks like crazy and won't start for about 15-20 seconds of cranking. Then it catches and idles rough for about 10 seconds and after that runs PERFECT. No idle issues, no surging or hesistating when driving. I've got a datalogger and have checked for CEL's and so far none have popped up. Any suggestions? I was thinking the coolant temp sensor or wire but I checked and the connection looks good. Is there any way to test to see if it is in spec?
Thanks!

 

[Redsand187]

If you ohm it out with a multi meter and compair it to the specs per temperature. I don't have the specs off hand, but I guess I could get them off All Data tomorrow if you really need them. Your logger should let you see the coolant temp reading.

You may want to look at your battery cables and terminals, to check for resistance when hot. It's shot.

 

[Paybax]

Your engine is flooding. You might want to get your injectors cleaned. Its something RX7s are famous for and that sounds exactly like flooding to me.

Also when you are cranking over your engine get some one to smell the exhaust or just the general area outside your car and see if they smell gas.

 

[karnsatron]

Check your air filter, spark plugs, wires.... The usual maintenance stuff.

 

[Taboo]

Your engine is flooding.

If the engine's flooding, it'd do so even when it's cold.

If the engine's hard to start when warm, the problem maybe in the fuel pressure solenoid (that closes on start-up and prevents the fuel from evaporating in the rail) - especially if one runs the stock fuel pump. The ECU has no feedback off the solenoid and won't throw a code. You can test the solenoid by pinching the vacuum line from the solenoid to the intake manifold (which prevents any vacuum going to the FPR if the FPS is stuck open) and see if the car starts easier. If it does, check the voltage in the FPS during start-up. If you see 12V, the solenoid is toast, if you don't see any voltage at all, the problem is either in the wiring or the ECU.

 

[Paybax]

No it wouldn't, my car was exactly the same way. It was fine when it was cold but once the engine got warm and the engine was shutoff it started to flood. With my car if i left it over night it would start up fine in the morning but if i would of took it out again that night it would of been flooded. I think the gas has time to expell through the system when it sits longer or something. I think it has more due to the time since you last drove the car then it has to do with engine temperature.

I would check for flooding first since its very easy to do.

EDIT: notice all of the i thinks

 

[Taboo]

No it wouldn't, my car was exactly the same way. It was fine when it was cold but once the engine got warm and the engine was shutoff it started to flood. With my car if i left it over night it would start up fine in the morning but if i would of took it out again that night it would of been flooded. I think the gas has time to expell through the system when it sits longer or something. I think it has more due to the time since you last drove the car then it has to do with engine temperature.

I would check for flooding first since its very easy to do.

EDIT: notice all of the i thinks

Explain how, why and what caused the flooding. The only way the gas can "expell through the system" is through the piston rings and end up in your oil pan.

 

[Paybax]

I have no idea but I do know that it works in the "real world". It might not working in theory but it does work. Also once I gotmy injectors cleaned the problem stopped. This was with a rotary engine though but injectors are injectors. Also a rough idle for a couple seconds is a charactersic of flooding also. Instead of cranking your engine over try getting a push start instead and check to see if black or blue smoke comes out your exaust.

 

[blackawdturbo]

Sounds like a fuel pressure solenoid that's bad and not allowing extra fuel to inject during hot cranking.

Edit: Oops, looks like Martin beat me to it.

 

[m[ohio]]

thanks guys. where is the fuel pressure solenoid located so I can test it?

 

[blackawdturbo]

thanks guys. where is the fuel pressure solenoid located so I can test it?

It's on the firewall next to the brake master cylinder reservoir. Just follow the vac line from the FPR back to it to make sure.

 

[Taboo]

I have no idea but I do know that it works in the "real world". It might not working in theory but it does work.

OK, you said the engine is flooding and then you argued that the engine wouldn't flood even when it's cold - but don't know why. If you don't know why the engine wouldn't flood even when it's cold, how do you know the engine would flood only when it's warm?

The FPS is there for a reason: To prevent fuel evaporation in the rail during start when the engine is hot. If the fuel is able to evaporate in the rail, picture what the fuel does if it ever gets inside the cylinders if the injectors leak. If the fuel evaporates in the rail and the injectors leak, the fuel pressure in the rail drops down to 0 psi and the only amount of fuel (if not already evaporated) that can get into the engine through the leaking injectors is equal of the volume of the rail itself - which is not enough to flood a hot engine.

Also a rough idle for a couple seconds is a charactersic of flooding also.

And what are the characteristics of engine running lean? Try to lean out the A/F ratio (with S-AFC - for example) and see how well the engine's going to idle. It's going to idle rough as well. Does it mean the engine's flooded and one should lean it out even more?

Instead of cranking your engine over try getting a push start instead and check to see if black or blue smoke comes out your exaust.

Trying to push-start the car won't do any good since the fuel pump is running when the key is ON. You might as well crank it.

 

[Paybax]

How do I know?? Because my car was the same way, didn’t you read that above? I know you are right but this is just something for him to look at. How can anyone say for sure what the problem is?

Have you ever tried to start a flood car? Some cars have an automatic fuel cut switch installed by the owner or by the factory. If you crank the engine with your foot to the floor it will not let any more fuel into the engine. So you engine will no longer be flooded when you take your foot off the pedal and just crank it over normally. So the end result is an engine that isn’t flooded anymore. But if you don’t even try to do that then try push starting it because it will force the extra fuel out and you will see black/blue smoke. If you just keep cranking the engine it won’t burn the fuel off but you will just smell all the gas out your tail pipe.

So what im saying it that it could also be a flooding problem and that’s something he should look at. I will say it again, I know you are right but this is just something else he can look at. You are a very smart man and I wouldn't question ya unless it’s something I have dealt with for years.

Please PM me if you want to discuss this further. There is no need to post all of this in here.

GL with your problem m[ohio]

 

[Taboo]

How do I know?? Because my car was the same way, didn’t you read that above?

Was your car a DSM? What if I told you that several of my and our customers DSMs were the same way and they never were flooded?

How can anyone say for sure what the problem is?

Knowledge and experience . One can analyse the symptoms an eliminate possibilities 'til he narrows the cause of the problem down. That's why I said that the car would flood even when cold. The engine may flood only for two reasons: too much fuel (= stuck injectors, mulfunctioning FPR, etc.) or weak or no spark (= ignition problem). In both cases, the temperature of the engine would not affect the results in any way and the flooding problem would exist even with the engine running (= the injectors wouldn't be somehow mysteriously stuck open or the ignition wouldn't work only during start-up when the engine is warm). Since the engine idles and runs fine once started even when warm, the problem is obviously in the events occuring during start-up. Since we can eliminate any ignition issues (since they would persist even after the engine would start) the problem is obviously fuel related and the only thing related to fuel that's happening during start-up is that the FPS closes the vacuum signal to the FPR to prevent fuel pressure decrease and fuel evaporation in the hot fuel rail - which consequently makes the car easier to start when the engine is hot. Once started, the FPS opens and the fuel pressure is regulated by the pressure in the intake manifold. It's easy to check by disconnecting the FPS line from the intake manifold and plugging the nipple on the intake manifold prior to trying to start the engine.
It's just a simple elimination process...
There's an easy way to check if the engine's flooding: Pull the spark plugs and see if they're soaked with gas.
You can't always base every advice on "my car was the same way" (especially if it even wasn't a DSM), otherwise you could be telling people that their cars don't start because they bent valves and now have to pull the head - because your car didn't start either when you bent your valves - and their problem could be in their fuel pump or CAS.

Have you ever tried to start a flood car? Some cars have an automatic fuel cut switch installed by the owner or by the factory. If you crank the engine with your foot to the floor it will not let any more fuel into the engine. So you engine will no longer be flooded when you take your foot off the pedal and just crank it over normally. So the end result is an engine that isn’t flooded anymore. But if you don’t even try to do that then try push starting it because it will force the extra fuel out and you will see black/blue smoke. If you just keep cranking the engine it won’t burn the fuel off but you will just smell all the gas out your tail pipe.

Yes, I think I've tried to start a few flooded DSMs in the 12 years I've owned and worked on them . Unfortunately, DSMs don't have any automatic fuel cut switch you're talking about as some other cars might have. The only way to force the fuel out of the cylinders (if flooded) is by removing the MPI fuse (to prevent the ECU and fuel pump from turning on) and cranking the engine over. It's much easier and less time consuming than pushing the car in gear and the key OFF down the street. Even if you do so - and the engine is no longer flooded, you haven't fixed the cause of the problem - and there's no point to pushing the car down the street if the engine starts on its own after being flooded - as you think it's happening in m[ohio]'s case. :dunno: