[seanzook06]

I know it is a topic that has been done to death, and I have hrowesed countless threads looking for an answer.
I have put a Vitara g16b ( 5 pin maf, Denso ecu) into my sierra, I have a crank no start issue. Fuel injectors have pulse, can hear Maf working, ignitor , and dizzy are also getting power as is TPS. 2 earths at the back of the manifold have battery earth voltage. I tried running it on Start ya bastard etc. But still nothing.
The symptom is it cranks, goes to fire and then stalls out.

I had a mate have a look at it, who does heaps of engine swaps, including g16b ( his experience is mostly baleno) he reckons it has everything it needs to start. I bought it as a known running motor, so I am hesitant to pull down
the motor to check timing etc. is there anything I should be looking for?
A few things to consider, I can't find a very readable wiring diagram for a 5 pin maf Vitara. I also did not pull the motor out of the Vitara originally.

[fordem]

You know what I don't see here - testing for spark. It won't run on starting fluid which suggests no spark, or spark at the wrong time.

Which distributor do you have - there's one with an integrated coil and one without - check for spark at the plugs and if there is none check at the coil.

[seanzook06]

Have checked for spark, I have the dizzy with separate coil. Have grounded plugs to confirm spark

[sideways]

Here's a 5 pin maf wiring diagram.

Indeed as Fordem says, if it's mechanically fine but wont run on ether then there's a spark problem. Have you pulled the fault codes? Have you set the ignition timing? Do you have correct fuel pressure while cranking?

[BlazeOrbit]

you might want to double-check the fuel pressure. Even if the injectors are pulsing, low fuel pressure could cause the symptoms you're describing. Also, verify the wiring connections and ground points are solid and correctly hooked up. Sometimes, a wiring issue or loose connection can be the culprit, especially with engine swaps. If everything checks out, you might need to look at the ECU and MAF sensor more closely or consult a more detailed wiring diagram for your specific setup.

[seanzook06]

Thanks sideways massive help, especially the diagram, I don't have an obd tool pull fault codes. I do have correct fuel pressure, timing is correct, potentially I do have weak spark, however there is clear spark jumping the plug to the manifold when I ground them.

[fordem]

A scantool is unlikely to be of any use - the Vitara you pulled the G16b from was, most likely, not OBDII compliant - it would have had a way to check for codes using a diagnostic jumper and the check engine light, but whether or not that part of the wiring has made it over into the Sierra is another story, as is the new location of the monitor coupler in which you'll need to install the jumper.

You say the timing is correct - are you talking about valve timing or ignition timing and how have you verified this? Get a timing light, connect it to the #1 plug and crank the engine, does it flash and does it flash at the right time?

It's my understanding that some of the distributor rotors for these engines can be installed incorrectly which could mean that even though you do get a spark, it's not at the plug you need it at, at the time you need it there.

[sideways]

seanzook06 wrote:

Thanks sideways massive help, especially the diagram, I don't have an obd tool pull fault codes. I do have correct fuel pressure, timing is correct, potentially I do have weak spark, however there is clear spark jumping the plug to the manifold when I ground them.

I can't tell you how pleased I was to find that diagram after finding so many of the newer 3 pin maf diagrams, there's very little out there for the early system.

You don't need a scan tool. Loop a wire in the terminals of the diagnostics plug and it flashes the check engine light as a code. The process and codes are outlined in this pdf.

[seanzook06]

Thanks guys for all the help, turns out there were no electrical or wiring issues, all it took was slight adjustment of the ignition timing and fresh plugs and leads. I was getting spark from the old plugs and leads, but it must have been weak. That and the ignition timing wasn't spot on