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By machineica
Hello everyone! My name is Michael and I swapped a GTI motor into my jimny.

I do not know why this engine won’t start. No injector pulse what ever I do. I am getting a code 33 and have tested the maf. Voltage on the vout is 2.5v while just key on. So need to find a maf somewhere.

Anyway the engine should still run with a bad or disconnected maf right?

I can leave the diagnostic terminal connected and can get a code 12 by cycling the key. Still no injector pulse.

I heard somewhere if the alternator isn’t hooked up the engine won’t start is that true?

I had to build my own harness from scratch so I have no idea how the alternator connects into the ECU wiring to even consider that. It’s not on any diagram I have.

Any auto sparky or anyone ever mess with a swap before? I have plenty of spark and will run on ether.

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By Instant_shine
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It could be a number of things…

Bad MAF, bad coolant temperature sensor, bad ecu.

Also in the harness (not ecu), there should be a tiny thing with the letters N.S. on it. Without it, the engine won’t run.

I recently had a similar issue. Mine was a bad maf sensor and a coolant temperature sensor.
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Do you have a FSM? Trying to trouble shoot without that will be difficult. Do you know what year the engine, wiring harness, and ECU are from?
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I’m feeling generous and I’ll list the trouble shooting procedure for no start, no injector pulse.

First I’ll post the MAF sensor flow chart:
Disconnect AFS (MAF) coupler and remove coupler seal to test voltage from back of coupler.
Check voltage at “W” wire terminal of coupler with ignition switch ON. Is there battery voltage?
“W” wire open or poor A3 connection. If wire and connection are OK, substitute a known good ECM and recheck.
With ignition switch OFF, connect AFS coupler.
Turn ignition switch ON and check voltage at “Vout” terminal.
Is it within 0.2 - 0.8V?
Poor AFS to coupler connection. If connection is OK, faulty AFS.
Clean air cleaner element.
Connect AFM to AFM outlet hose as shown in figure and clamp it securely.
Start engine and check voltage at “Vout” terminal.
Does voltage rise as engine speed is increased?
Faulty AFS
Open “B” wire or poor A6 ECM connection.
If wire and connection are OK, intermittent trouble or faulty ECM. Recheck referring to “Intermittent trouble” on p. 6E-34.

I would also check the WTS first also. For basic injection time the ECM uses both CAS and AFS sensor, but uses TPS, WTS, and battery voltage, and O2 sensor to make comresation to injector time.
However the injectors should go into fail safe mode if plug AFS is disconnected and still pulse.

Fuel injector circuit check
If non of 4 injectors makes operating sound.
  1. Disconnect coupler “C” from ECM with ignition switch off.
  2. Check continuity or volatage between such terminals as listed below. Is continuity or specified voltage obtained?
Terminals Coninuity or voltage
  1. Between C3 and C8 continuity
  2. Between C5 and body ground continuity
  3. Between C2 and body ground 10-14V at ignition switch ON
    If not in 1. Injector signal wire open or poor coupler connection.
    If not 2. Injector ground wire open or poor engine ground.
    If not in 3. Injector power wire open.
Poor both C3 and C4 connections, both C8 and C9 connections, both C5 and C10 connections, both C5 and C10 connections or both C2 and C7 connections.
If all above are OK, substitute a known good ECM and recheck.

Igintion Signal Circuit (ignition signal not inputted). Ignition signal is sent from the ignition coil primary circuit. Monitoring this signal, ECM detects whether the ignition spark is emitted or not and stops injector operation when this signal is not inputted. I don’t think any of the GT(i) used a standard ignition coil that I see you are using. You might be missing the power unit (I think that has the igniter built into it), and noise suppressor. I cannot tell what distributor you have also, but it needs to match the ECM and wiring that you have. Post up what ECM you have and a shot of inside the distributor, and the rest of the ignition system you are using.

Good spark?
Faulty ignition system
1.Disconnect ECM coupler with igntion switch OFF.
  1. Is battery voltage applied to A12 terminal at ignition swithc ON?
    Faulty noise suppressor or open circuit between ignition coil and A12 terminal.
    Poor A12 connection.
    If connection is OK, substitute a known good ECM and recheck.
This is from a 91 FSM. In 92 to 94 is similar but has some changes to ESA (electronic spark advance).

If I get a chance I’ll post some pin out for ECM and ignition system diagram.
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