GTi not starting problems, does crank

[Marty3480]

Hi all, 99 GTi 1.8T AGU
Yesterday I installed a Diverter Valve because when bought the car it didn’t have one (crazy I know). It has a fmic and cold air induction with silicone intake.
I recently have replaced the valve cover gasket as I was getting oil on the spark plug wells but didn’t start it till I had the DV installed.
Sooooo, took it for a short test run and only got to second gear when the engine lost power and died on me. When I changed from 1st to second it made a backfire type sound but I don’t think it was a backfire (not as loud).
I towed it back into my garage but still can’t get it started (does turn over). I have also recently replaced the following: crank angle sensor, coolant temp sensor, ignition amplifier, spark plugs.

Any help is appreciated

[HaydEn]

Ground or wiring issue from removing the valve cover?

Does it have fuel? Does it have spark?


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[Marty3480]

I’ll clean up the ground and see if that helps... yes has spark but will check the fuel pump relay also

[mgiannelis]

From what you have said. It kinda sounds like the fuel to air might be too lean. Have you made any mods to the ECU settings ?

[Marty3480]

No ECU mods that I’m aware of, I’ve only had the car for a few months. I find it really strange that adding in the diverter valve is the only real change and the gear shift made it die

[h100vw]

Is the diverter stuck open?

[Marty3480]

Ok, so it was running rich so checked all of the intercooler pipes and found one had come loose. Thanks for all of the replies, it’s now running great.