4 second start delay

[mattd1979]

Has if anyone had an issue with a delay in the ignition switch when starting on a 1990 Q45. I have to hold the key in the start position for 3 to 4 seconds and then it will start. I have already swapped the relay out of another Q that we have that works fine but there is no change.Matt

[Q45tech]

Install an ACCURATE fuel pressure gauge [located at the from fuel filter rubber line where it fits on the metal line feeding engine] so you can see if the fuel pressure falls after sitting so that there is not an immediate correct pressure to start..............bad anti drain back valve in fuel pump or a bad fuel pressure regulator?

34 psi cranking fuel psi.

[elwesso]

during that 4 seconds is the motor cranking?

[mattd1979]

The starter will not engage until about 4 seconds of holding the key in the start position.

[3Q Jay]

try turning key ON and waiting >5 sec. then does the starter engage immediately at start position?

if no, then what is happening (electrical conditions--voltage/current) during the 4 sec delay?

[mattd1979]

This doesn't happen all of the time but it does happen more times then not.You ask what happens. Well, I turn the key in the on position, then I tun it to the start position and hold it until the starter begins to run. Once in a while the starter will run as soon as I turn the key but most of the time when I turn it and hold it in the start position, it takes about 4 seconds before the starter runs and turns the engine over.

When I hold the key in the start position, everything is the same when it has the delay just as it is when it doesn't have the delay. Nothings seems different. I have tried jiggling the key while holding it in the start position but nothing changes. I still wait 3 to 4 seconds regardless if I am jiggling it or not.
Modified by mattd1979 at 8:32 PM 11/25/2007

[mattd1979]

I thought that I read a post here a while back about someone else that had this same problem that I have but I couldn't find the post thru the search.?

[Q45tech]

The commutaor on the starter could be corroded and the brushes near the end of their lives, same with the starter internal relay.

Take it out and disassemble and clean or replace.Analysing the current waveform during start is useful if you can find someone with the necessary test equipment..................300 amperes can be examined by wraping a few turns around starter to battery cable and looking at the resulting voltage with a digital storage oscilloscope.

http://www.amazon.com/dp/B000I...e=asn

http://www.picotech.com/auto/w....html