Hard Starting when Hot (1Z TDI)

Hi,

I have the 1Z engine from a 97 Passat TDI in my bus.

My swap is well sorted and has not always had this issue. Now I see an intermittent hard start when the engine is hot.

Hard start = few seconds of cranking before starting.

Previously, this would would happen when I had the IQ set a little too lean. I tried richening it up and that doesn't seem to help.

Any pointers much appreciated.

Mark

What the IQ at????

RoseBud68 said:

What the IQ at????

Click to expand...

I am running bigger nozzles + Malone 1.5-ish tune.

It was at 9.2. Today, I just dropped it down again to 8.2 to see if I am still running too lean.

I'll see if it's too smoky and if it starts better when hot tomorrow.



Thanks,
Mark

Have you had it down more around 4-5? Pump timing is also important there, or the starter could be starting to build up some internal resistance when hot. Used to have a mk1 that would only start when cold and went longer than I should have before changing it, just praying I didn't stall

Just curious but isn't a 1.5 tune meant for stock nozzles?
Fill me in...

1.9ZOOK said:

Just curious but isn't a 1.5 tune meant for stock nozzles?
Fill me in...

Click to expand...

No that's Stage 1.... 1.5 is upgraded injectors.

^ it's just torque limited to what the stock injectors will do.

gotcha

Owain@malonetuning said:

Have you had it down more around 4-5? Pump timing is also important there, or the starter could be starting to build up some internal resistance when hot. Used to have a mk1 that would only start when cold and went longer than I should have before changing it, just praying I didn't stall

Click to expand...

Pump timing looks OK (advanced but within range). The starter itself is OK - -the engine spins fast enough.

My injectors are DLC1019's.

I called the tune 1.5ish. Really it was a Malone 2, with some torque removed at lower RPMs .(I had Mark Malone do that when I thought the reason that my transaxle broke was because of too much torque. Turns out it was something the rebuilder missed. I'm OK with staying detuned -- I am getting 30 MPG+ and can go 75 MPH no problem)

As I recall when the IQ was lower (4-5), the mixture was way too rich. I'll try richening more and see and post back. I figured it was either too lean or losing prime, but not sure why prime would be worse with the engine hot.

Thanks for all the help!
Mark