Johny zoom

iTrader: (5)

I have about 1300 miles on my rebuild. It starts fine when its cold : 3000 rpm and then 1500 almost perfect.
The problem is when its warm I seem to have to push the gas petal to get it to start. once started it runs great no stumbles or anything. I have checked tps and BAC
Thanks Johny

Johny zoom

iTrader: (5)

anyone

Johny zoom

iTrader: (5)

bump

thesatanicmechanic

Before you begin troubleshooting the hot-start assist mechanism, confirm a few basics. Have you performed the appropriate grounding mods to the egi & engine harness? Recheck idle settings: Bypass mode & check curb idle speed & base ign. timing.

One you have started the engine, does it idle normally? Are you positive there are no additional symptoms which may clue you in to an accurate diagnosis?

j.p.

thesatanicmechanic

If you need to know how to troubleshoot the hot-start assist, shoot me a PM or I can post pretty simple instructions here.

j.p.

RunningDeer

How about doing it here, so I can read along too

thesatanicmechanic

K, here it is:

During a hot restart, the (engine control unit) ecu engergizes the pressure regulator control solenoid valve (hereon referred to as the prcsv), which interrupts the vaccuum signal to the fuel pressure regulator for 90 seconds after the engine has started (50 seconds on a turbo). The ecm also opens the IAC (boc) to wide open to provide additional air.

Step 1, eliminating the Intake air temp sensor as the culprit, very quick test. On your warmed up engine, shut off, remove the IAT connector & install a 2-3k ohm resistor across the connector, start the engine. If the IAT is bad, the engine should operate fine. Idle @ 100 rpms above your base adjusted idle speed & then settle down to your normal curb idle speed.

IAT sensor range values:
68F 37-45Kohms
122F 10-13Kohms
185F 3.1-3.8Kohms

Step 2, on a warmed up engine, disconnect the fuel pressure regulator vaccuum hose. Start the engine, there should be NO vaccuum to the FPR for 90 seconds, then vaccuum should occur. Test the the PRCSV valve: Engine off, disconnect the vac. hoses, attatch a vac hose to port "a", the port sticking out the side beside the solenoid vent. You should be able to blow through & have air exit at port "B", the one at the bottom of the solenoid. Next remove the electrical connector from the PRCSV & energize it with 12volts. Aside from it going "click", when you blow through it air should now exit through the vent, NOT port "B".

The PRCSV is located just behind the grey switching solenoid valve, on the engine, behind the alternator, closest to the firewall. This is on a N/A, I don't know if turbo's are in the same location. I hate to refer to solenoids by their color becuase I have seen solenoids installed from other engines & positions, regardless of color.

I can't stress how important it is to make sure that your your ECU is sufficiently grounded. The shitty splice in the factory harness at the ecu is craptacular. So is the grounding point that the splice connects to on the top of the engine. Do the grounding mods first!

The ecu depends on this ground to energize all of the solenoids under its control. Solenoids don't require hardly any current to stay open but an ASSLOAD to initially energize, especially 15 year old ones. Your ecu supplies the ground to energize the solenoid, the +12vdc comes from the EGI main relay & is always "hot" in the on or start position.

I'm no RX7 expert, but I know electronic fuel injection, it's how I pay my bills.

A few P.S.'s here: The signal wire from the ecu to the PRCSV is blue/orange.

I think that the "threshold" value for the IAT to the ecu for hot-start assist is around 10Kohms, but I cant confirm that.

Good luck.

Do your grounding mods.

j.p.

Johny zoom

iTrader: (5)

Thanks for your help, grounding mods top of my list now.
My idle is low even if I turn it all the way it only raises a little. Its a n/a automatic trans. I love getting feedback from someone who knows what they are talking about.
Thanks again.