I have a HQ Holden with a Mongoose M80 (~2009) alarm, immobilizer. Lately I have had starting issues, initially went through replacing the battery, serviced the start motor but still persists, and seem a little random.

I currently think it is either in the start switch mechanism or immobiliser circuit? The car will crank at least half a turn some times many turns then cranking will stop dead. It is on gas so requires plenty of cranking before starting if it has sat for a while. Sometimes eventually it will go other times I give up. Before disassembling the steering column and start swicth etc I would like to discount the immobiliser. Is it possible it is a wiring issue with the immobiliser or electrical fault with the unit it self? General if it is the starter on a HQ you can push the steering column and get a start connection. The only way to get it to crank again is to turn off the ignition and start again?

thanks

I have the same problem in my VL (on gas) with a cyclops immobiliser when the battery gets down a bit and you need to crank it for a while to draw the gas in.

Cranking for a long time will cause the car's voltage to drop, and most immobilisers will "re-arm" below a certain voltage thinking someone has disconnected & reconnected the battery in an attempt to bypass the system (their default power-on mode is to immobilise). Because mine is a transponder (dongle) style unit, all I do is turn the key off, then back on, and because the dongle is within range, it automatically disarms again (as the system voltage returns to a normal state while it's not cranking over). Sometimes I had to do this 3-4 times to get it going if I left it for a month or so.

My solution - I bought a C-tek MXS 5.0 charger that I leave connected when the car isn't used for long periods, and I haven't had the issue since.

But I think blue light's suggestion of getting a gas primer to make it fire quicker is probably going to be one of the easiest ways to solve your issue.

We finally got to the bottom of the trouble. Turned out to be a few things combined that lead to the utes troubles.

1. First we found there was only 8V getting to the starter from the harness. A common enough issue with old cars, wiring and ignitions circuits.

Solution: We added a relay and ran 12V direct from the battery. This help immensly.

2. After checking the batery we noticed it was only at 12.5V. The alternator had the smallest wire in existence running to the battery so though that could be the problem, however after using a jumper lead (monster sized cable) there was no difference and found the alterator was charging a bit, but not enough.

Solution 1: Ordered a 105A Delco alternator from Kingswood country and installed

Solution 2: made up a decent sized (similar to mainlead to eart/starter on battery) alternator lead and installed.

Result not only do we have a great charge to the battery, the starter motor just about jumps out of the engine bay when starting. Bonus is power supply is now 120%!!! No longer do I suffer the issue of head lights going up and down with revs - 105A and a good cable give more than enough power for lights, spotlights, stereo and anything I can plug in.