Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: ttpower on March 01, 2016, 06:43:59 PM

Title: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 01, 2016, 06:43:59 PM
The car started fine, ran out of fuel outside the house(was stood for a while) then after lots of attempts to start, burned the starter motor.
So changed for a new starter motor, she started up straight away and would only idle, any gas and would cut out.

Now she not starting at all. At first it tried to start, now it just doesn't even attempt too.

I've done the following;

1) Cleaned plugs. They kept getting soaking wet of fuel after cranking so changed injectors to standard rails (were aftermarket before). Now seem to be normal with little fuel but still no attempt to start.
2) Checked injector wiring (lightbulb test) and operating ok.
3) Fuel pressure when cranking is 42psi
4) Have spark.
5) No fuel leaks.
6) cant see any boost leaks (very few vacuum lines as single turbo)
7)Not done compression check, but when plugs out have even, loud swoosh noises.

When cranking PFC shows 8 & 0 degrees for IGN.

I've also noticed that when cranking over,in the PFC Sensor screen the PIM, VTA 1, VTA2 highlight and voltage shows 0.00V. This is only when cranking, when the key is just in the on position they are not highlighted and show correct voltage. Is this normal?

Anyone have any ides what to try next?


Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: clive on March 01, 2016, 07:34:50 PM
Unfortunately from your No1 I would say it is still flooded,  :-[

In the past I have towed cars for 1/4 of a mile that have been flooded like this before they chug into life.   
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 01, 2016, 07:35:08 PM
Thats is strange...sorry to state the obvious but have you done a full deflood....fuel pump relay out and sparks out and crank til no fuel mist....?
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 01, 2016, 07:36:01 PM
Lol 2nd time this week Clive posted a second b4 me!
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 01, 2016, 07:40:12 PM
Thanks for the advice guys. Yeah done the full de-flood........plugs out, loas of mist until cleared. Plugs were soaking wet with fuel, cleaned and dried them, put them in..............still nothing, not even an attempt to start.
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 01, 2016, 07:48:58 PM
As Clive said try a towstart?
Ive blowtorched sparkplugs to dry them out in past.
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 01, 2016, 07:52:55 PM
Would be hard to tow as quite low  ::)
How about easy-start spray? When you say blow torch, u mean to heat them up....would new plugs be best bet?
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 01, 2016, 08:01:06 PM
Yes new best but if dont catch and foul them up ive removed and warmed them up.
The replacement starter new or used just wondering what its cranking speed is?. Does seem strange that fired and idled and died on throttle....
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 01, 2016, 08:02:59 PM
My mate used easystart on his ran til he ran out of easy start...he had problem with the syphon in his tank in his rx8. Got it running but not something ive done.
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: clive on March 01, 2016, 08:42:14 PM
Quote from: boosted on March 01, 2016, 07:36:01 PM
Lol 2nd time this week Clive posted a second b4 me!

I like a good close race  ;)
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 02, 2016, 09:55:35 AM
Ok, ordered some new plugs today to try out and give a go with some easy start see if it does the trick. Its cranking at 200rpm with the new starter.

Can someone confirm if there PFC sensors "PIM, VTA1, VTA2" highlight when there cranking over?

Seems bit strange that these drop to 0.0v when cranking.
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: bin liner on March 02, 2016, 11:35:20 PM
Take the plugs out and main fuse out.  Turn over until mist clears. Leave plugs out overnight.  With main fuse out turn the car over the next day to clear any settled fuel.  Put in new plugs and put fuse back in and fire it over.  The plugs are probably knackered now so definitely change them.  Also connect up a second battery via jump leads to give you some extra oomf  when turning over...worst case add a couple of drops of atf into the plug holes and turn over then put in plugs and try and start.  That will help build a bit more compression.  Dont rev it and let it idle. it will smoke alot...hth
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 03, 2016, 08:54:02 PM
ok, so put new plugs in and new leads....same thing not starting or even catching. Tried with some easy start and she started firing but still no start.

Anyway, I plugged out the electrical plugs to all the injectors and only connected up the secondaries using the primary connectors. She fired right up, and started to hunt. Traced a loud hissing leak to the secondary injectors where the injector goes into the manifold, so ordered some new seals. For reference the part number for these are NF01-13-257A (Lower Secondary Fuel Injector Grommet). They should be here in a few days so hopefully will resolve the issue.

Just a quick question, would this vac leak actually prevent the car from starting?

Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 04, 2016, 06:58:12 AM
When you ran out of fuel it was idling on the primarys sounds like 1 or more injector air locked or youve got an primary injector down? But when you lightbulb tested injectors sounds like 1 plug not seated afterwards?
Should prime easy in couple of cranks...so i think it was flooded and possibly a bad connection on a primary injector after removing? All speculation though.
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 04, 2016, 11:42:28 AM
Yeah it was idling fine then soon as any gas it cut out.
Both primary injector electrical plugs were showing to run fine and now with them in the secondaries the car is starting and idling but just hunting. When I got it started this time it only started to hunt when she got warm so was able to trace the leak. I'll try these new seals when I get them and if still having issues will take out the primaries and get them cleaned.
Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: boosted on March 04, 2016, 04:46:13 PM
you got a multimeter? you can test the resistance of the injectors, dont know wether these are high or low impedance but sure the net would yield the results but they both should be the same so theres a start...
last year i had a misfire on an rx8 engine that led me on a merry dance i tested my own injectors and cleaned then myself....
1. i wired up the injector to a 12 v power supply and using a syring and bit of airline i forced the syring plunger in and enabled me a clean the injector with cataclean and also 2. verify spray pattern and 3 verify actually open when 12 v on.
bit heath robinson but proved injectors where not at fault.

Title: Re: Help Rx7 FD Wont Start - Have fuel pressure & spark
Post by: ttpower on March 09, 2016, 09:41:42 PM
Ok, finally sorted it.

Firstly, sorted the leak out on the secondary rail by installing in the original rubber o rings into the intake manifold.
Lastly, found out the standard primary injectors were stuck closed (some that I purchased to take out my ID ones)....changed them over for a spare set and fired right up.

Cheers for the help guys.