89 NA Vert

After doing a hard pull the other day my car has started having terrible bogging and hesitation problems.

It starts like normal and will drive under very light to no throttle but the moment I give it any bit a throttle it cuts out. I can limp the car all the way through the gears but if I push past 3k rpm it pretty much becomes undrivable and wants to backfire and hesitate even down in the low 2k rpm range. Any quick throttle blip basically kills the car and makes it pop and bang like crazy. It feels like it’s getting no fuel but it could also be my ignition. I change the wires and plugs last fall so I doubt that’s the issue though. I pulled the fuel pump today and changed the sleeve filter on it to no avail. The inside of my tank looked very clean with no rust, just a little varnished fuel in the bottom but I don’t think it was nearly enough to cause issues. My best guess is the fuel pump is going bad but before I go buy one I’d like some advice.

Thank you

 

if it's bogging out below the 3688 RPM transition point for secondaries then i would agree that it sounds like you have a fuel related issue. a simple test is to hook up a pressure gauge and mount it to the windshield(put it under the wiper arm) and take the car for a drive.


don't forget, these cars do have a fuel filter near the engine, they can and do clog up. the hose off the fuel filter where the hose meets the hardlines on the engine is what you should be attaching between for fuel pressure testing.

if you are losing fuel pressure i would then move on to monitoring voltage to the fuel pump when the problem occurs. you may have a fuel pump relay issue. i have also seen improper fuel hose that is not submersible use rated on fuel pump installs which caused the hoses to swell and rupture, limiting fuel pressure as most of the fuel bypasses right back into the tank but a few PSI can be seen.

 

I’ll get a pressure gauge sometime this week and try that out, do you know where the fuel pressure should be at? When I pulled the pump it looked like the one they sell on Atkins if that makes any difference. No idea if it was their turbo or N/A model though, would’ve been done by the previous owner

 

it should be roughly 40psi, it will vary some with loads while driving but no more than 10psi difference.

if you clamp off the return line the peak pressure should be 71.1-92.4psi, engine off.

 

I haven’t been able to test the pressure yet, still waiting on the gauge to come in. I did pull the UIM off though and have a pretty dark puddle formed on where the engine and LIM meet. It doesn’t have much of a smell and I’m thinking it may be oil. Not sure if this could be related.


I also Change the Fuel filter which seem to help for a little bit. Took it for a drive and it was fine, then the next day I took it out again and it was back to square one

 

silicone vacuum lines with zip ties aren't really ideal for use as oil metering lines. i suspect one or all of them are seeping/leaking.

i always use teflon/PTFE hose with stainless braided outer layer, similar to what brake lines use.

 

Good to know, thank you. This car is full of small headaches from the previous owner