1996 Infiniti I30 Hard start

[jhayes9835]

I have a 1996 Infiniti I 30. I recently had the engine replaced with a used engine. I replaced the engine because of blown head gaskets. After the engine was replaced, it is very hard to start. When it eventually starts, the engine runs great. The used engine started and ran great before it was installed into my car.The mechanic has checked all of the sensors, (MAF, crank, etc) checked the wire harness for breaks or frays, checked the ignition switch, and checked the computer. Everything he has checked was fine.I am at a loss. The engine turns over but will not catch. When the engine turns over you can hear it cough or backfire, but will not start.

The coils are only 8 months old. I think he used the injectors that were in the used engine. He did say that the ignition key has to be in a certain position to get spark to the coils. When he checked the ignition switch, he got a new one and just plugged it in to the connector and used a screw driver to turn it on. Would the key assembly make a difference?Any ideas? What else can we look at to solve this problem?

[MinisterofDOOM]

Unfortunately, with this problem following a full engine swap...it could be any of a huge number of things. Hard to say without seeing the car in person. It could be a security/immobilizer issue.

[loystock]

Looks like you have a problem with the Ignition Lock Cylinder so he has to go straight into the Ignition Switch to start the car. But this has nothing to do with the hard starting or backfiring.

First check that the battery connections are clean and tight and that the battery voltage is >12.5VDC. Ensure all ground connections are secure - battery ground, engine/transmission ground and the main engine harness ground points (near intake plenum). Have an OBD II scan for trouble codes. Some faults may no turn on the CEL.

Check the air intake for leak. Double check the condition of the Crankshaft Position Sensors and related connectors/harnesses. Either one of these can cause hard starting and backfiring.

Do a 'spark' test of the spark plugs. Check the ECCS (ECM) relay

If all of the above are OK, check fuel pressure - 34 PSI with engine running, 43 PSI with Ignition ON but engine OFF (limited to @ 5 seconds). Also, something could have gone wrong when he swapped the fuel injectors. Do a 'click' test of fuel injector for basic operation. Bear in mind that an injector may be clicking but there could be internal problem with it.

[clydeotis]

i am having same problem i swapped my 2000 infiniti with another motor and it is so hard to start. when it does start it runs great . i have put 2 new crank sensors, a new cam sensor, a new maf sensor , had the ecu rebuilt, i checked all the related wires for short to ground , short to power and they are all ok.it is getting harder to start .i just let it sit on my driveway now i try to start it every day but i have to hit the starter about 10 or 15 times to start it.so i gave up . don't know what to try next. thanks for any help .

clyde

[clydeotis]

hey jhayes i feel for you if you find out what it is please let me know and i will do the same for you thanls

clyde

[loystock]

Does the Security LED turn off when Ignition switch is ON? Did the dealer reprogram the ECU after it was rebuilt? The ECU contains the NATS (Nissan Anti Theft System) Ignition Key ID which could have been corrupted/wiped out when the ECU was rebuilt. So the Ignition switch can detect your Key ID but not the ECU, thus the starting problem. Make sure the sensors are installed correctly with the connections clean and tight.

Also, check and clean the main engine harness ground points, near the oil filler cap. Check fuel delivery pressure -34 PSI with engine running and 43 PSI with Ignition ON, engine off (5 seconds limit). You need a T-fitting for a fuel pressure gauge between the fuel filter and the fuel rail.

Unless you have recharged the battery, it should be weak by now after so may start attempts, making it more difficult to start the car. Make sure the battery voltage is >12,5 VDC. If not, have it re-charged or jump start the car.