1.7 Fuel Injection problem, Experts chime in! Options

[IronHillRestorations]

I've got a customer car here that's giving me some trouble.

To make a very long story as brief as possible, it's a '71 1.7 I've put new trigger points, ignition points, condenser (rotor & cap are like new), plugs look OK, injection tests out fine on my Ninefourtronics test set, fuel pressure is good when running bu it does leak down about 10 psi when you shut off the engine (I thought it should hold pressure), new vacuum lines (and yes I've double checked the routing to make sure it's correct). The engine has a different intake plenum (maybe out of an autostick 411??) and had no AAR, a cracked air intake elbow, bad vacuum lines and fuel lines, and some other problems. It is going to get the fuel pump relocated and new fuel lines, and a fuel tank cleaning or replacement.

The only issue I've had is after running it for a while the only way you can start it is with the throttle pedal to the floor. If you don't floor it, it will just crank and crank, It's suspicously like a vapor lock, but the car's got over 1/2 tank, and it's just not that warm here.

Otherwise it starts on the first or second crank by just turning the key. The engine is tired and close to the end of it's current service life, but this is kind of strange. I have the mixture pot on the ECU set fairly lean, as it seems to run best there.

The only other issue I've got is that the idle speed bypass screw is really at the end of the limit to get it to the correct idle speed, but my guess is this could be the fact that the engine is weak.

If you have a good opinion on this, I'll take it. Oh and no it's not my car so don't tell me to chunk the FI! (IMG:style_emoticons/default/smile.gif)

[dr914@autoatlanta.com]

Hi Perry. Advance weights stuck or head temp sensor failing! (maybe?)

[r_towle]

Hi Perry. Advance weights stuck or head temp sensor failing! (maybe?)

(IMG:style_emoticons/default/agree.gif)

Clean the distributor plates.

Rich

[toon1]

Hi Perry. Advance weights stuck or head temp sensor failing! (maybe?)

Hi Perry. Advance weights stuck or head temp sensor failing! (maybe?)

(IMG:style_emoticons/default/agree.gif)

Clean the distributor plates.

Rich

Is there a lack of power? what rpm does it idle at? if the weights where stuck A: there would be a huge lack of power. B: the rpm's would not come down after a drive. the weights would be out, advancing the timing, keeping the rpm's up.

If you need to keep the pedal to the floor after a drive and the motor is warm, the engine needs more air for ignition, sounds like leaky injectors. A motor does not need a whole lot of fuel to start after a drive with the engine warm. there is a fine line between starting back up and flooding.

eaisiest way to tell is to run the car and pull the injectors right after and check the tip for fuel leaking.
OR

Repeat the hard start scenrario without depressing the pedal, before the car starts check the plug see if it's wet or smells of excess fuel.

If it fires ok cold ( if the injectors are leaky) the fuel has had enough time to evaporate and the pressure has bled off the sys. so there is no extra fuel and the sys. is back to normal.

you would be supprised what can get past a fuel filter. I found small rust flakes coming out of my injectors that where bypassing the filter.

It does not take much to stick open and injector.

Keith

[orange914]

d-jet doesnt take vacuum readings does it? if it does the worn engine could cause a mixture difference but probably rich with low comp. what about the cold idle valve, i would think that too would richen not lean out (IMG:style_emoticons/default/confused24.gif)

[toon1]

d-jet doesnt take vacuum readings does it? if it does the worn engine could cause a mixture difference but probably rich with low comp. what about the cold idle valve, i would think that too would richen not lean out (IMG:style_emoticons/default/confused24.gif)

what do you mean by vac. readings? The cold start vavlve is a good one (fith inj.), and should be checked.

If you are refering to the AAR as the cold start valve, that is basically a vac. leak at idle for a COLD engine and would make the motor lean when warm( more air) AND would be highly noticable at idle. It's possible it could be partially open. If it was missing in the beginning it should have been replaced with a working one!?

[dr914@autoatlanta.com]

Hi Perry. Advance weights stuck or head temp sensor failing! (maybe?)

Hi Perry. Advance weights stuck or head temp sensor failing! (maybe?)

(IMG:style_emoticons/default/agree.gif)

Clean the distributor plates.

Rich

Is there a lack of power? what rpm does it idle at? if the weights where stuck A: there would be a huge lack of power. B: the rpm's would not come down after a drive. the weights would be out, advancing the timing, keeping the rpm's up.

If you need to keep the pedal to the floor after a drive and the motor is warm, the engine needs more air for ignition, sounds like leaky injectors. A motor does not need a whole lot of fuel to start after a drive with the engine warm. there is a fine line between starting back up and flooding.

eaisiest way to tell is to run the car and pull the injectors right after and check the tip for fuel leaking.
OR

Repeat the hard start scenrario without depressing the pedal, before the car starts check the plug see if it's wet or smells of excess fuel.

If it fires ok cold ( if the injectors are leaky) the fuel has had enough time to evaporate and the pressure has bled off the sys. so there is no extra fuel and the sys. is back to normal.

you would be supprised what can get past a fuel filter. I found small rust flakes coming out of my injectors that where bypassing the filter.

It does not take much to stick open and injector.

Keith

CLAIRIFICATION:

If stuck slightly (meaning the distributor rotor will not spring back), the timing will not be retarded enough for an easy startup

[toon1]

that's true, that would be noticeable while cranking? It want's to fight itself and kick back with advanced timing.

More info is needed.

[pbanders]

The only issue I've had is after running it for a while the only way you can start it is with the throttle pedal to the floor. If you don't floor it, it will just crank and crank, It's suspicously like a vapor lock, but the car's got over 1/2 tank, and it's just not that warm here.

Generally, when you have to hold the throttle wide-open to get a car to start, it means that it's flooded. You said the pressure leaks down, too. My guess is that you've got one or more leaky injectors. After the car sits when hot, the injector leaks into the cylinder, flooding it. Check the injectors to see if they're dribbling gas once the system is pressurized.

[pbanders]

Oh, and D-Jet has a known design flaw with hot start, anyway. Too rich, leading to hard starting. Add in a leaky injector and you get to where you are with this car.

[dr914@autoatlanta.com]

that's true, that would be noticeable while cranking? It want's to fight itself and kick back with advanced timing.

More info is needed.

The slight advance does affect starting when hot but what I had mentioned first and that is a failing head temp sensor I think would be more on the money

[toon1]

Agreed, about the CHTS. It sound like the motor is hard to start when warm. It would seem to me that is it where a CHTS it would be a cold start prob.


either way, it should be checked


Has it been replaced? maybe it's wrong!

[Bleyseng]

The only issue I've had is after running it for a while the only way you can start it is with the throttle pedal to the floor. If you don't floor it, it will just crank and crank, It's suspicously like a vapor lock, but the car's got over 1/2 tank, and it's just not that warm here.

Generally, when you have to hold the throttle wide-open to get a car to start, it means that it's flooded. You said the pressure leaks down, too. My guess is that you've got one or more leaky injectors. After the car sits when hot, the injector leaks into the cylinder, flooding it. Check the injectors to see if they're dribbling gas once the system is pressurized.

(IMG:style_emoticons/default/agree.gif)

send the injectors out for cleaning or just order a set. Busdepot had them for $39 each new. Made a huge difference in Blairs Black 1.7 72.

[mightyohm]

Aren't injectors $200 ea now?

[Bleyseng]

some places yeah, but I sourced some from 1.7L ones from BusDepot for $39 each new.

run, don't walk if ya gots a 1.7l (IMG:style_emoticons/default/chair.gif)

[TravisNeff]

At www.busdepot.com

I see rebuilt ones for 34.95+12 core = 46.95 each.

searching for part number 0 280 150 009 I see $73.03 for new

Where did you see that killer price again?

[TravisNeff]

Bump