Another Engine Surging thread JRICHKER?

[bdazzgt]

Check your vacuum lines and make sure the line to the carbon canister is capped and not leaking. The code 85 indicates that the canister purge solenoid has been removed, so the leftover plumbing poses a possibility for vacuum leaks.

I only have three vaccum lines, one to the Brake booster, one to the Adjustable Fuel pressure regulator, which is Y-ed with the hVAC controls under the dash, and the PCV valve, all lines are new, the rest is capped, i have no SMOG controls, modules, canisters ect on car.

 

[jrichker]

I only have three vaccum lines, one to the Brake booster, one to the Adjustable Fuel pressure regulator, which is Y-ed with the hVAC controls under the dash, and the PCV valve, all lines are new, the rest is capped, i have no SMOG controls, modules, canisters ect on car.

Sharing the vacuum line on the fuel pressure regulator isn't a good idea. The fuel pressure regulator should have its own dedicated vacuum line with no other devices on it. That prevents fluctuations in vacuum from affecting the fuel pressure.

 

[bdazzgt]

Sharing the vacuum line on the fuel pressure regulator isn't a good idea. The fuel pressure regulator should have its own dedicated vacuum line with no other devices on it. That prevents fluctuations in vacuum from affecting the fuel pressure.

So this could be my problem and choking the fuel out at idle without enough vaccum? or when i turn on my HVAC controls that sucks vaccum out of the fuel pressure regulator?

 

[bdazzgt]

bump

 

[Chuckman]

Well I put on a new module and it didn't work. Ive been driving the car a lot. The problem seems to be when I am decelerating and the engine is warm. Most of the time if I allow the car to slow in gear and just brake without downshifting bringing the rpms to 1000ish the car will idle fine once i push the clutch in. It seems the motor cant compensate for the drastic drop in rpms what would cause this? Codes are the same as above idle is around 800 TPS .98v. Im outta ideas guys

i had problems like that, iirc i had the timing set a bit too high for the combo and idle a little low. i had replaced most of the sensors, switched back to stock 19lbers/maf, and all that, and it still did it untill i backed the timing down to 12 (from the 14 that the stock motor liked) and boosted the idle up to 900-1000rpm.

 

[jrichker]

So this could be my problem and choking the fuel out at idle without enough vaccum? or when i turn on my HVAC controls that sucks vaccum out of the fuel pressure regulator?

It may not specifically be your problem, but it is bad engineering practice. You could have a vacuum leak in the HVAC system and never know about it. That would affect the fuel pump regulator's ability to control fuel pressure.

 

[bdazzgt]

If the fuel sump was lose in my gas tank would that also cause this? I put gas in last night closed the hatch and heard it moving around in the tank, well i assumed it was the sump clanking around.

 

[groovygroveone]

I have seen some TPS,do good when cold ,but as they warm up and get hot.The surging begins.Even Though you have a fairly new tps.It still could be bad. One minute it could send a good signal to the ecm,and other times bad signal causing the surging,possible miss or skip!

 

[bdazzgt]

i will try and replace the TPS, i have an extra one lying around

 

[bdazzgt]

So i have a Comp 270xe cam 218*/224* .512/.512 114lsa, i do not have a vaccum canister on the car, my dad swears up and down this is my problem. I have ran this motor in two other cars that were carbed with same cam/stock heads and it never had idle problems. Could this be an issue also?

 

[bdazzgt]

Yesterday I had all day to work on the car, got more diagonstic information, I bought a vacuum tester. The car pulls around 11mm of vaccum at idle. If I create a vacuum leak ie pull off a hose it idles fine and the vacuum goes to 22ish on the meter. I bumped the timing to 16* which is a little high I know but the vacuum improved signficantly and so did the idle quality. Could the timing be a factor on this problem? I bumped the fuel pressure to 38lbs with vacuum off and re ran the fuel pressure regulator to its own vacuum instead of y site it off the HVAC controls. Im open to any suggestions

 

[jrichker]

If your timing is off, it will affect the idle.

Do not try to set the ignition timing without a working timing light. The auto parts store near you may have one to rent or loan if you do not have one or desire to purchase one.

Paint the mark on the harmonic balancer with paint -choose 10* or 14* or something else if you have NO2 or other power adder.

Be prepared to always run Premium gas (92-93 octane or better) if you go past the stock 10* timing.

Remove the SPOUT connector (do a search if you want a picture of the SPOUT connector) It is the 2 pin rectangular plug on the distributor wiring harness. Only the EFI Mustang engines have a SPOUT. If yours is not EFI, check for a SPOUT: if you don’t find one, skip any instructions regarding the SPOUT
Warning: there are only two places the spout should be when you time the engine. The first place is in your pocket while you are setting the timing and the second is back in the harness when you finish. The little bugger is too easy to lose and too hard to find a replacement.

Connect timing light up to battery & #1 spark plug.

Start engine, loosen distributor hold down with a 1/2" universal socket. Shine the timing light on the marks and turn the distributor until the mark lines up with the edge of the timing pointer. Tighten down the distributor hold down bolt, Replace the SPOUT connector and you are done.

The HO firing order is 1-3-7-2-6-5-4-8.
Non HO firing order is 1-5-4-2-6-3-7-8

 

[bdazzgt]

is 16* to much timing to run? I run 94 octane because it is the only gas that doesnt have ethanol in it to begin with, in know it might be overkill.

 

[jrichker]

The 16° is a little high, I would stick with 12°-14° degrees.

 

[bdazzgt]

Well it died today ran good for two days then died at a few intersections FML. Im tired of dealing with this any other suggestions