HOW TO DO AN ADVANCED SEARCH.

Mon Jul 08, 2013 3:56 pm by Admin


For the benefit of 944Hybrids users there are two search functions available for you to use.
The purpose of this sticky is to explain the "Advanced Search" function because it is much more powerful and is the best choice when researching information.

When you log on to the site a list of options is shown in a line at the top of the page. One option is labelled "Search", use this option (NOT the search box lower down on the right).

After you click on the upper search option, a drop down box appears. At the bottom of this box is a radio button marked "Advanced …

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Running rich???

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Running rich???

Post  fliermike45 on Wed Jan 11, 2012 6:58 pm

I think my engine is running rich, there is a fine black coating on the rear of the car and after idling at a red light the engine stumbles and misses then smooths out. No problems when rolling in any gear.

I suspected the temp sensor and checked with OBDII scanner and it seems to be working OK. Before the first startup the fuel injectors were pro cleaned and flowed.

Initial idle when I first ran the car was 1800 rpm but I have got that down to 1100 by adjusting the physical throttle stop. The Throttle body is a cable type and is new with new sensors.

Any Ideas please?

Just finished first 100 miles and it's awesome, had to change the clutch master cylinder but that's a simple job. Noticed that I have a oil weep from my sloan supplied oil pan, will live with that for a while.

Uprated LS/Mazda brakes as per Xschop work fine with a manual Willwood cylinder, yet to try a high speed stop yet.

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Re: Running rich???

Post  944-LT1 on Wed Jan 11, 2012 7:44 pm

Check for vacuum leaks and exahaust leaks before the O2?

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Re: Running rich???

Post  Arthropraxis on Wed Jan 11, 2012 9:58 pm

Have you had the motor street or dyno tuned? BTW, I had a pan from Sloan that leaked, sent it back. Several months later the replacement came back and it had a leak, too. Whoever welds for him sucks.




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No tune

Post  fliermike45 on Thu Jan 12, 2012 7:48 am

Everything stock, no tuning, checking for vacuum leaks.

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Re: Running rich???

Post  948 on Thu Jan 12, 2012 11:08 am

Yes, check for vacuum leaks....

fliermike45 wrote:Initial idle when I first ran the car was 1800 rpm but I have got that down to 1100 by adjusting the physical throttle stop.
I would suspect that issues are linked. If the IAC and TPS are not doing their job, or you have a huge vacuum leak, fueling and idle quality will def be affected. Did you try my suggestions regarding the TPS etc? [You must be registered and logged in to see this link.]
What were your findings?

Also, how old it the fuel in the tank?
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Running rich

Post  fliermike45 on Thu Jan 12, 2012 11:58 am

948, Yes I tried the things you suggested and it made no difference.

The throttle body and it's sensors are new along with the 5 wire MAF, both came from SSP wiring who did the harness/computer. I have changed the temp sensor in the Driver's side cylinder head. Also checked that the intake manifold bolts are tight. The injectors were serviced and flow tested.

I have followed Xschops idea and plumbed the PC valve directly in the line from the rear of the driver's side valve cover. I have tried disconnecting this line with the engine running, no change even when I block the inlet tube on the manifold. The inlet tube on the driver's side of the intake manifold that's opposite the PCV connector is blocked off. Breather ports on pax side valve cover are blocked off as per Xschops plan. Vacuum connection on rear of engine has two outlets, one is blocked off (I think that was the old servo connection) other outlet goes to HVAC ports on the firewall via the reservoir tank and on to the heater/recirc valve . Also tried disconnecting this outlet and blocking it with the engine running, no change.

I have never removed in the intake manifold, guess that's next to check the gaskets.

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Re: Running rich???

Post  xschop on Thu Jan 12, 2012 12:05 pm

Mike, Are both your heads grounded? I had issues at first until I grounded the rear side of BOTH heads. I believe the headgasket material is not a good conductor on these engines.
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Grounding

Post  fliermike45 on Thu Jan 12, 2012 12:21 pm

Rob,
I'm assuming that would impact on the spark plug performance?
Will try that. Thanks

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Re: Running rich???

Post  xschop on Thu Jan 12, 2012 12:25 pm

Diddo. My entire driver's side bank was not firing when I drove it to the exhaust shop...should have seen the stares I was getting on that trip. I pulled the plugs when I got it back home and they were all soaked. Grounded the rear driver's head (pass head and block were already done) and never had a problem since.
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Re: Running rich???

Post  xschop on Thu Jan 12, 2012 12:34 pm

Also +2 on the old gas. If it is an ethanol blend and been setting for a long time, it becomes acidic and can gel then clog new injectors instantly on top of the fact it is hygroscopic and will take on water from atmosphere if there is any weep hole in the system.
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Re: Running rich???

Post  spence on Thu Jan 12, 2012 12:36 pm

Mike, did you pull your plugs? I had a similar problem and I rented a noid light to check to see if the injectors where all firing (they where). I ended up having two bad brand new plugs.... You can check for vacuum leaks with propane. Just open the valve and spray around the intake and listen for changes...

Also, how do you like your brake set up? I've got the same setup (ls430 / rx7 & willwood manual master); it stops the car fine at low speeds. It seems you really have to put some leg into it to get them to lock up at higher speeds... But it guessing that's the way manual brakes are supposed to feel? How is your pedal travel? Mine gets pretty close to the bottom of the car before they lock up... I may have to bleed them again but I'm not sure...
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Rich

Post  fliermike45 on Thu Jan 12, 2012 12:48 pm

Gas is fresh as I drained the tank when I installed an uprated fuel pump.

I have not pulled the plugs as this engine runs well just fast idle and rich, it stumbleas after sitting at a red light but clears quickly, still points at a rich micture.

Surely if the O2 sensors sensed unburnt fuel the computer would weaken the micture??

As Rob suggested I'm going to ground the heads next.

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Re: Running rich???

Post  xschop on Thu Jan 12, 2012 1:10 pm

Hey Mike, glad to see you are about to get the final bugs worked out. How is the steering issue? I have decided I will only build shafts for the Borgeson joints like I posted. The DD shafts can be trimmed very easily for length adjustments and it makes for a very easy shaft removal process when the time comes.
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2 things

Post  fliermike45 on Thu Jan 12, 2012 1:44 pm

Rob,
I used my VOM and checked the heads to block resistance and there is zero ohms. The block has a ground strap to frame.

With the AN to metric adapter in the Turn One PS pump drilled out to 1/8 th. inch the PS is fine when driving on the road. Its stll notchy when manouvering but I remember when I installed the 17" wider wheels before the V8 swap, the steering feel changed and that felt different. The car was off the road for 18 months so I had forgotten how it feels (felt).





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Re: Running rich???

Post  948 on Thu Jan 12, 2012 1:50 pm

What did the data logs look like for the TPS and IAC during warm up?


fliermike45 wrote:Surely if the O2 sensors sensed unburnt fuel the computer would weaken the micture??
O2's will sense a rich mixture but they can only do so much to the fuel maps. Have you confirmed that your ECM is going into closed loop? Do you have any codes? What are your fuel trims looking like?
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Re: Running rich???

Post  Rich L. on Thu Jan 12, 2012 1:58 pm

Hey Mike. What are you using for a fuel pressure regulator? If not the Chevy unit, could the pressure be too high? If the Chevy unit, any chance it's in backwards. I was staring a pictures the other day and am feeling a little unsure of which connection goes where.

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Re: Running rich???

Post  aixgelo78 on Thu Jan 12, 2012 3:18 pm

Was talking to someone about my throttlebody and he mentioned this:

FYI... when swapping over the top sensor or the iac, please be sure to keep an eye on the red rubber o-ring that seats the sensor. it sometimes stays lodged in the original t/b and i quite often get cores with the o-ring still inside. high or erratic idle is sometimes possible without the re installation of ring.

Hope it helps.

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OBDII read

Post  fliermike45 on Thu Jan 12, 2012 3:43 pm

Just ran the engine with OBDII connected

TPS 8.6, Speed 1190, Load 3.9%, MAF 1.5, MAP 8.0 Coolant 196 deg f, IAT 102
Ign Adv 35.5, Fuel Syst 1 and 2 Clsd., O2 S11 .8, O2 S12 .44, O2 S21 .9

ST FTRM 1 varies 0 to 3.9 (Should this be RT? Constantly varying)
LT FTRM 1 fixed at 14.6
ST FTRM 2 varies 0 to 2.3 (Constantly varying)
LT FTRM 2 fixed 14.8

Vehicle speed 0

Fuel Pressure 55 on gage in fuel rail.

This is my first experience with a Computer controlled fuel injected engine.

Using Corvette fuel pressure regulator as specified in Sloan's book.

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Rich

Post  fliermike45 on Thu Jan 12, 2012 3:52 pm

Aixgelo...thanks, just pulled the sensor you mentioned, it has the red O ring.

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Rich

Post  fliermike45 on Thu Jan 12, 2012 5:16 pm

I had my fuel injectors serviced and I have sent the flow data that to SSP wiring who did the work on my PCM. They are now telling me that the PCM needs adjusting for the higher fuel flows and my fuel pressure. Hope this the problem with the mixture.


Last edited by fliermike45 on Thu Jan 12, 2012 5:55 pm; edited 2 times in total (Reason for editing : typo)

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Re: Running rich???

Post  aixgelo78 on Thu Jan 12, 2012 9:29 pm

fliermike45 wrote:I had my fuel injectors serviced and I have sent the flow data that to SSP wiring who did the work on my PCM. They are now telling me that the PCM needs adjusting for the higher fuel flows and my fuel pressure. Hope this the problem with the mixture.

I didnt really get a good vibe from SSP in regards to PCM programming. They are the ones that convinced me that speed density was OK. A few weeks later, they said how much better MAF was. They also was the one that said "buy" our mail order tune, we have a sale. Now that I'm ready for some changes, they said that its just to get me "running" and I cant rely on it as a full tune. (which I knew, but they made it sound so much better than a base line)

Hope you figure it out. At least you are so close.

Chris


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Re: Running rich???

Post  948 on Fri Jan 13, 2012 7:25 am

fliermike45 wrote:Just ran the engine with OBDII connected

TPS 8.6, Speed 1190, Load 3.9%, MAF 1.5, MAP 8.0 Coolant 196 deg f, IAT 102
Ign Adv 35.5, Fuel Syst 1 and 2 Clsd., O2 S11 .8, O2 S12 .44, O2 S21 .9

ST FTRM 1 varies 0 to 3.9 (Should this be RT? Constantly varying)
LT FTRM 1 fixed at 14.6
ST FTRM 2 varies 0 to 2.3 (Constantly varying)
LT FTRM 2 fixed 14.8

Vehicle speed 0

Fuel Pressure 55 on gage in fuel rail.

This is my first experience with a Computer controlled fuel injected engine.

Using Corvette fuel pressure regulator as specified in Sloan's book.

TPS looks okay, if that value is %. The voltage should be about 0.43 volts.
STFT will switch around
LTFT, at 14.8%, is quite high and suggests compensation for a lean condition. The following link is explains fuel trims. [You must be registered and logged in to see this link.]
The MAP value looks very suspicious, what unit of measure is that? And what number of Bar is the sensor?
Your timing is way off! At idle an LS should be in the 15-18 degree range (WOT is around 28 on a stock LS).

What is your IAC? That should be 30-50
Read this too. [You must be registered and logged in to see this link.]
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Re: Running rich???

Post  pormgb on Fri Jan 13, 2012 7:29 am

fliermike45 wrote:Just ran the engine with OBDII connected

TPS 8.6, Speed 1190, Load 3.9%, MAF 1.5, MAP 8.0 Coolant 196 deg f, IAT 102
Ign Adv 35.5, Fuel Syst 1 and 2 Clsd., O2 S11 .8, O2 S12 .44, O2 S21 .9

ST FTRM 1 varies 0 to 3.9 (Should this be RT? Constantly varying)
LT FTRM 1 fixed at 14.6
ST FTRM 2 varies 0 to 2.3 (Constantly varying)
LT FTRM 2 fixed 14.8

Vehicle speed 0

Fuel Pressure 55 on gage in fuel rail.

This is my first experience with a Computer controlled fuel injected engine.

Using Corvette fuel pressure regulator as specified in Sloan's book.

LT FTRM 1 fixed at 14.6
LT FTRM 2 fixed 14.8

When you have positive LTFTs (long Term Fuel Trims) you PCM will add fuel because it thinks the motor is running lean, this typically happens when you O2s are in closes loop and they are not seeing the right fuel mixture.
Positive LTFTs are typically caused by exhaust/intake leaks, wrong fuel pressure or an incorrect tune, there are various tables that control mixture at different engine states (open/closed loop, cold, warm, under load). I don't think your problem is being caused by exhaust leaks because your LTFTs would indicate you have the same leak on both sides (LTFT almost equal), so it could be intake/Vacuum or tune.
A proper running LS1 in closed loop would have -5 to +5 LTFT activity, LTFT number indicated the percentage of fuel to be added or removed to bring the AFRs back to the commanded AFR (typically 14.7) at idle and when coasting.

You may want to invest in a Wide-Band O2 sensor, that's the only way you'll know you have the right AFRs, I run dual Widebands and always keep an eye on them.

With regards to fuel pressure, this is typically set to 58 PSI, from my experience you would have be below 50 PSI to have mixture issues. I would also get someone to look at your tune, if you have no mechanical issues the problem lies with the tune.
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Rich

Post  fliermike45 on Fri Jan 13, 2012 8:25 am

Thanks guys, you mostly believe this is a tune problem.
The PCM is going back to SSP Wiring as they commented on my injector flows and need to adjust the PCM.


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Re: Running rich???

Post  pormgb on Fri Jan 13, 2012 9:26 am

fliermike45 wrote:Thanks guys, you mostly believe this is a tune problem.
The PCM is going back to SSP Wiring as they commented on my injector flows and need to adjust the PCM.


That would make sense!! There is an IFR table that must reflect the correct flow of you injectors, the IFR table works with you fuel pressure and if its not correct the PCM can't correctly determine commanded fuel.
When fuel injectors are upgrades, the IFR table has to be changed, there is a spread sheet that's used to generate IFR table values.

Good Luck!!

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