245 1987 Starting Problems.

waynej · Post by **waynej** » 12 Mar 2009, 11:29

Wife's car doesn't want to start, must crank for 2-5 minutes. After about 20-60 seconds it fires on 1 cylinder,after another 45-90 seconds it begins firing on 2 cylinders, after another 45-60 seconds it fires on three and the starter is no longer necessary, but takes another 30-60 seconds to fire on all four. When running there is no missing and idle is smooth etc. In warmer weather it will sometimes keep running on 2 cylinders without the starter.This began about a month ago and was only an occasional problem. When it began happening more often I replaced the 20 amp injection fuse and fixed a vacuum leak. It started perfect for a couple of days and then got worse again. Now it only starts normally about one time out of 15. Had to put in a new battery as the old one would not crank long enough.
Thanks for any helpful suggestions.

Post by **billofdurham** » 13 Mar 2009, 13:29

When you replaced the battery did you check that the earth (ground) connection had a good, clean contact where it meets the body? Also check the earth strap from the engine/gearbox to the body.

There are several possible causes for poor starting:
Bad or dirty connections on the ignition and plug circuits.
Air intake leakage.
Fuel pressure incorrect.
Temperature sensor defect. The engine has two temp sensors one for the gauge which is mounted in the head under intake header #2. The other is for the fuel injection and is mounted in the head under intake header #3. This sensor is a negative temperature coefficient thermistor. As the temp drops, the resistance rises, and as the temperature rises, the resistance drops. Therefore, if you have a broken wire, defective sensor, or even just a bad connection the resistance measured by the sensor and passed to the ECU will be very high or even infinite. The ECU interprets this as minus many degrees and pours in the petrol to compensate. This would lead to the type of starting you are experiencing.

Sensor resistance "cold" should be around 6,000 ohms at 32 degrees F (0 deg C), 2300 at 68 degrees F (20 C), and 200 at 212 F (100 C). You can also check the wiring between pins 13 and 5 at the LH ECU, with the sensor disconnected, resistance should be infinite. Voltage with the ignition ON and sensor connected, measured between pins 13 and 5, should be:
0 C=around 3 volts +/-.5v
20C=around 2 volts +/- .5v
100C=around .3 volt +/- .1v
If these aren't correct, check the connections in the sensor wiring harness. Check engine earth connections at the intake manifold. If the voltage is zero, your ECU is at fault.

I hope this helps.

Bill.

fredbyte · Post by **fredbyte** » 17 Mar 2009, 22:05

Also do all the normal tune-up procedures: new spark plugs, new distributor cap and rotor, and new spark plug wires.

Paul240480 · Post by **Paul240480** » 25 Mar 2009, 08:47

Another check-point in relation to afore mentioned air-leaks.

Injector seals, if you'not replaced them before I'll lay odd that there leaking if only a bit. Also check air-inlet manifold gasket. Spray car-cleaner or similar whilsts its ticking over, if the idle settles, that'll be the cleaner temporarily sealing a leak.

Good luck.