Hi all,

I was hoping you'd be able to help with my 1989 6 speed. I've owned the car a little over a year and done about 12k miles in that time.

Last summer when getting petrol after a short run, the car wouldn't start, like it was flooded. I tested the resistance of the multec injectors and sure enough a few were well out of spec.

I ordered the Bosch III's from FIC after rave reviews and my mechanic fitted these, along with new AC Delco FR5L plugs, dizzy cap, rotor and silicone leads. The car ran sweetly, felt better to drive but I noticed a drop in MPG, to low 20's at best on the motorway. Previously I was able to get 26+

Once again the car is hard to start if I pop out to get petrol it won't start unless I leave it 10 mins then it fires. From cold it takes a couple of cranks to splutter into life. My MPG is dire. I get about 12 around town and 18 on the motorway. The car spits flames on most gearshifts apparently.

I tested the fuel pressure, it started on 0. Turning the key to the first position made it rise quickly to 42psi. With the engine running it's in the high 30's. Then when I shut it off, it drops about 1psi a minute. If I remove the intake boot and open the throttle blades, I smell petrol. Likewise, at the rear of the car by the filler cap I can smell fuel.

I checked and double checked the plug leads and have pulled the spark plugs, they're consistent and all look fine. I bought a stethoscope but couldn't hear the injectors dripping with the engine off.

I feel like I'm looking at more than one problem here. To make it more frustrating, I'm in the UK so it takes a week for parts to get here and Jon @ FIC isn't about to just send out 8 injectors for me.

Please help!

 

If you just turn the key on, hold then off without starting the car - how long does fuel pressure hold? Sounds like it might be the fpr.

 

High 30psi is barely enough pressure! The typical OE fuel pump has a check valve. Your rail system should maintain the 42psi. average - 1 hour. engine off. You are leaking fuel for sure. If the regulator is leaking. most likely, will smell fuel in your vacuum lines.

 

Sorry, should have said I pulled the vacuum line on the fpr and no fuel was present. The pressure drops about 1psi a minute with the pump primed. I'm still thinking it's injectors? Even though I don't have a stand out sooty plug?

 

Set the timing correctly.

 

Any luck?

 

When did you last change o2 sensor(s). They can cause a rich condition. I have been looking at fuel injectors and notice a few different psi, did you replace them with stock pis injectors?

 

Hi guys, thanks for the help. That O2 sensor is in tight!

Anyway, had a look at the coolant temp sensor again and noticed the wiring was damaged by the connector. I think I've found my problem? I've cut it off and will get an electrician in work to extend the wires so I can crimp it back on again. There were barely 3 strands intact on each.

 

Oh yeah, could very well be your problem. You could solder on the new pigtail and wire. But nice find, and report back

 

Nope, no change. It stumbles into life and my economy is still rubbish. I'm thinking I must have a dodgy injector or ecm?

 

Any chance you can hook up a scanner to it to look at the data?

Gary

 

How are you calculating mileage? With the fill up and the trip meter or what?

 

Verified dash readout by filling tank, driving and refilling tank. What's a good scanner? I'm UK based

 

An old Tech1 or a SnapOn MT2500 will work. Those are older scanners and shouldn't cost as much as a brand new one.

 

Hi

From Australia where we have petrol too

I have Bosch 3 injectors in my 85 and a fuel pressure gauge fitted to the shrader port on the fuel rail, I have 40 to 42 psi fuel pressure and it also does not drop to zero instantly when i shut her off.
It stays at 40 psi for at least 15 minutes, very slowly drops.

You can fault find by blocking of the fuel return hose at the fuel tank, turn ignition on for a couple of seconds and see if the fuel pressure stays at 42psi. Same with the fuel supply from pump, run engine and when you turn of the ignition get someone to clamp the fuel supply hose at the tank.

I had a similar issue with hard restart with my original injectors, there were a few that leaked and dropped to 0 psi straight away.
Pretty much flooded the engine, would need some accelerator pedal to get it to start when hot and turned off for a short while.

The rapid drop in fuel pressure can be due to leaky injectors, fuel pressure regulator not sealing. Or the pulsator / fuel pump in fuel tank between fuel pump and sender pipework, most just replace the pulsator if cracked or just because they do not like to reuse it.
Fit a small length of fuel hose and clamps and you are good to go.

My dash will show 25mpg cruising on a highway, i did also notice a drop in range however i had done many mods ...

You should get between 300 to 400 miles out of a tank, i was getting over 300 miles with a supercharged 383 auto and 3.07 rear gears.

There has been talk of the ecm chip needing to be adjusted for different injectors, Did you get 19lb or 24lb bosch 3 injectors?
I believe the late 80s used 19lb injectors, only the 85 had 24lb but lower fuel pressure regulator.
However the ecm would adjust the fuel injection pulse width to compensate and learn to compensate for a slightly larger injector.

My injectors are 24lb have the numbers 2 280 155 715 on the side, they are a grey slightly blue color.

Am sure FIC have tested the injectors before shipping them, they stand by their products.

Good luck and don't forget to check your ignition timing, Remember the outer ballancer ring can slip.
You could think 6 dbtdc but may be retarded, that would greatly affect fuel economy.
Confirm at TDC on compression stroke and timing mark is aligned with the harmonic ballancer mark.

Check the usual culprits, oxygen sensor and check the catalytic converter or pre cats are not clogged.
Check mufflers make sure you feel the same pressure / flow out each side, i feel for you UK petrol is expensive...