Del Sol Si - Hesitates under load

[drkyle96]

1994 Del Sol Si with 5 speed, purchased used one month ago (EH6)

 

Symptoms

Under heavy acceleration less than 3000 RPM the car runs rough, almost like one or two cylinders are missing.

It never happens over 3000 RPM.

If I accelerate lightly it does not happen.

It usually happens in higher gears (3rd, 4th, 5th) when going up a hill. In these cases downshifting eliminates the roughness/ hesitation

 

Tests Run

I thought initially it was fuel related and as its history was unknown, I replaced the fuel filter - no help

I tried higher octane fuel (I know, unlikely) - same result

I checked the resistance of the spark plug wires - they were in spec

I checked the engine compression - all cylinders were within 5% of each other

I replaced the spark plugs (again unknown when last done and had out for compression anyway) - no help

I took off the distributor cap - the rotor and points seem fine

 

Then two days ago I noticed a "skip" at idle. It doesn't appear to affect the RPM (I was watching), but the whole engine seems to blink off for the briefest of moments.

I don't know whether these two are related or are separate issues.

 

Any suggestions would be appreciated.

 

Thanks

[mpearce1974]

1994 Del Sol Si with 5 speed, purchased used one month ago (EH6)

 

Symptoms

Under heavy acceleration less than 3000 RPM the car runs rough, almost like one or two cylinders are missing.

It never happens over 3000 RPM.

If I accelerate lightly it does not happen.

It usually happens in higher gears (3rd, 4th, 5th) when going up a hill. In these cases downshifting eliminates the roughness/ hesitation

 

Tests Run

I thought initially it was fuel related and as its history was unknown, I replaced the fuel filter - no help

I tried higher octane fuel (I know, unlikely) - same result

I checked the resistance of the spark plug wires - they were in spec

I checked the engine compression - all cylinders were within 5% of each other

I replaced the spark plugs (again unknown when last done and had out for compression anyway) - no help

I took off the distributor cap - the rotor and points seem fine

 

Then two days ago I noticed a "skip" at idle. It doesn't appear to affect the RPM (I was watching), but the whole engine seems to blink off for the briefest of moments.

I don't know whether these two are related or are separate issues.

 

Any suggestions would be appreciated.

 

Thanks

 

Now that is one hell of a nice post! My first thought was dizzy? Perhaps igniter, or coil??

 

 

 

Oh and +1 rep point for not posting yet another my car no worky whats wrong post!

[DelSolSweetie]

agree with mike about good post! lol

 

 

could be something as simple as slightly clogged injectors.. you can get some seafoam and run it through the gas and intake

 

 

[lastresort576]

throw a timing light on it and see how that is. and for the hell of it clean your thermostat ground.

[SpeedDemon]

how many miles are on the car? could have bad carbon build up.

 

run some seafoam through it.

have the injectors sent out to be cleaned or get new ones

 

 

as for the "blinking" it could be a bad miss. which could be related to bad injectors or timing like jeff said

[Shanebot90]

You may have replaced spark plugs, but have you replaced your wires as well? Try the easy/cheap stuff before you jump to any other conclusions.

[DelSolSweetie]

i thought that too

 

until i reread the first post that said wires are carrying current correctly

[hiemsnox]

its always worth checking your fuel pressure if u can get your hands on a gauge.

 

my thought is dirty injectors though,

 

and also from what my mechanic friend told me... i guess with hondas the internal coil that creates the spark for the dizzy or something goes bad and thats why u sometimes see hondas with a external blaster coil... (when its not being used for a "performance application" Im not really sure what i'm talking about but maybe someone else will

[drkyle96]

Thanks to everyone for their suggestions. I plan to check the igniter and coil according to Helm's this weekend.

 

I already tried to run a Gumout fuel additive with the higher octane fill-up, but had never heard of the Seafoam. I checked their website and may pick up a bottle this weekend.

 

In regards to the mileage question, the car has 125k.

[cmgogo]

actually my first inclination is timing.

 

When I did my timing belt i was off by 1 tooth, and it gave me the same symptoms your are stating, check your timing, odds are your off.

[lastresort576]

actually my first inclination is timing.

 

When I did my timing belt i was off by 1 tooth, and it gave me the same symptoms your are stating, check your timing, odds are your off.

 

yup, thats kinda my thoughts..hesitation always usually plays out as timing..Not once have I actually seen dirty fuel injectors/filter be the issue.

[drkyle96]

I apologize for the long delay between posts, but I was away on business and ordered a timing light from Amazon.

 

It finally arrived and I verified that the electronic timing was dead on. I then decided to check the TDC position of

the cam. Kudos to Cory (et al). It was off by one cog and I noticed that the distributor was tilted to one extreme dimension.

I moved the cam, then adjusted the electronic timing back via the distributor. Now everything is dead on. The result is that

the "blink" where the engine cut out at idle seems to be gone. However, the hesitation under load is still present.

 

I looked at the injectors, coil and igniter, but Helms referred to a CEL for each if there had been a problem and I am not seeing any CEL's.

 

Next I purchased a fuel pressure gauge (again amazon, again waiting...). If the fuel pump and manifold pressure sensor

check out, then I will send the injectors to be cleaned.

 

I found two places on-line: injector rehab and TLF Performance. Does anyone have any experiences with either?

 

I also saw an another post referring to using Techron, so I may stop and give it a go while waiting on the gauge. Perhaps

the polyether amine will work better than the petroleum distillates that I already attempted.

 

Thanks again.

[drkyle96]

The Techron did not help.

 

The fuel gauge arrived and the fuel pump and fuel pressure regulator were found to be fine (35 psi with vacuum engaged; 45 psi with vacuum pinched).

 

When purchasing the Techron, I also saw a bottle of the "famed" Sea Foam on the shelf. I bought a bottle of the spray version.

 

So, I sprayed it into the throttle body. The hesitation went completely away for about 5 minutes, the time it took me to eliminate the massive smoke plume exiting from the exhaust.

 

I thought it might just have been a temperature phenomenon, so I sprayed it again. Again, the hesitation went away for the 5 minutes it took to burn off the petroleum distillate.

 

I feel like I'm now pretty close. I have a hard time believing that it's an injector. Why would it be sporadic? Is there something in the throttle body that could be sticking?

 

Thanks again.

[captn38]

I have been experiencing exact problem, started approximately at 180K miles, currently have 239K on my 93 DelSol Si. I have done all the same checks and or replacements you have made. Now convinced that replacing my distributor assembly is probably what is needed, since it contains the CPS and TDC sensors that cannot be replaced separately, not to mention a couple of your other responses seem to validate this notion. My big problem is like many, I do not wish to waste money needlessly, yet I am willing to pay for good quality. Distributors I have seen from third party after market to Genuine OEM Honda range from about $80 to almost $700. This a quite a price range margin. obviously they cannot all be alike in quality so are there any suggestions for a good grade/quality OEM type distributor without having to pay the excessively marked up Genuine Honda OEM prices.

[Raley]

used.... just stay away from distributor king... they are their own things...