Can A Faulty Fuel Pump Cause Poor Cold Start + Misfire Issues?

[ATK 140 1 Cars]

Been thinking through my cold start issue. When starting from stone cold the revs die and hunt and you have to hold throttle at 1500rpm, at which point there is a misfire. Misfire then clears and she idles fine. Engine idles and runs great from then.

 

The following are new: ign amp, tachymetric relay, CTS, AFM, throttle body, plugs, ht leads, dizzy cap, rotor arm, plugs, vac advance, battery. SAD is good. Injectors were sorted about 2yrs ago.

 

Could my cold start issues be caused by a fuel pump that isn't priming? When turning the key it is silent and you cannot hear the pump priming. Was wondering whether it was taking longer for fuel to reach the injectors as its not priming, hence causing this cold start troubles?

[ATK 140 1 Cars]

Any ideas and if this could be an issue any guides for swapping out the fuel pump?

[Anthony 1,003]

Unlikely in my opinion.

 

Most 8v's don't seem to prime either at all or certainly consistantly in my experience.

 

Insufficient fuel pressure at the injectors tends to show up as it trying to fire but not actually starting for a few seconds before it eventually splutters into life. You can prove it easily enough by just hard wiring the tachymetric relay for a few seconds to pressurise the system before starting.

 

What you're experiencing is almost always a setup issue - these cars are so sensitive to setup to get cold start to work nicely, but with persistance it can be largely addressed. What's always the most difficult is stopping it stumbling after it first fires without having to "catch" it on the throttle, especially in the depths of winter, but past that a reasonable cold idle is achieveable.

 

If it's hunting, lean the idle mixture off 2-3 turns (anti-clockwise) and see if that improves things at all. If it does, try another couple of turns. That alone won't fix it completely, but it will hopefully lessen it - it's a balancing act though, as you'll end up making hot idle so lean that it'll "chug" if you go too far.

[ATK 140 1 Cars]

Thanks Anthony for your reply, thats a great help, I will try leaning it off a touch, although I did have it set at 1.5% CO.

 

With my limited knowledge and experience I've done the setup as best I can via the Haynes - but if you don't catch the revs on the throttle, it cuts out. If you don't hold the revs enough it drops down and cuts out.

 

I'll try leaning it off a bit more. Getting there slowly, replaced and checked most things so I have to be narrowing it down by now!

 

Reason I thought it might be the fuel pump as there's a misfire for 40 secs or so when starting, which I thought wouldn't be caused by a poor setup issue.

[stufarri 98 3 Cars]

Best £30 I ever spent was go get a mobile tuner out to sort the fuelling/running issues. They are few and far between now but the CTI ran far better after 30 mins of testing and tweaking by the tuner.

[ATK 140 1 Cars]

Yeah I'm booked in to go see a tuner who has been recommended by some on here, so hopefully he will be able to sort me out. Fingers crossed!