1.6 16v fuel pressure

[GearHead]

Anyone know what the fuel pressure should be for the 16v mpi in a sidekick.

thanks
steve

[Fullload]

engine idleing and the vaccuum hose connected to the pressure regulator should be 29.8 to 37 PSI

This is what i found in the Haynes manual. They say you need fancy adapters and such to check and should be done by the stealership.

You think the regulator is faulty?

[GearHead]

I was just wondering.
I checked the fuel pressure at the rail and found it to be about 30 psi. thought this was low for mpi.
I know that some work had been done on the fuel tank and i wonderid if someone had swapped the tank for one out of a 8v, i did not know that the fuel pressure were simmilar.

Also there was very little fuel coming out of the return line.

Well i guess i'll keep looking for the cause of the idle problem

next i think i will drain the tank completely and add fresh fuel. i already added 1/2 a tanks to what was there but the old fuel might have been really bad.

later
steve

[Depot]

If I member correctly.. stock fuel pump should put out between 80 and 110 psi for the MFI's. 30 sounds very low. Check ur fuel filter and lines for obstructions or pinches.

gl

D

[GearHead]

That sounds more like what i expected for the mpi.
I thought it ran higher pressures that the tpi.
I guess i will have to check with the dealer tomorow., anyone got a FSM handy??

I have a feeling that the gas tank was swapped. Somthing tells me that it is a tank from an 8v engine.
They guy i bought it off say that the thank had been repaired/replaced buy the previous owner

i'm getting fuel and the filter is new, but i dont get alot of fuel "returning" to the tank. Its a very slow dribble.
Funny that i was able to drive the thind from brampton to hamilton, like i said it was ok on the highway but would not idle.

Thanks for the info guys.

later
steve

[Depot]

funny thing though.. when fullload and I were looking through spec books, it showed 1.6 8's running a higher pump psi than the 16 valves... again, this is ancient history so im not 100% sure.

Check ur pressure in the line b4 it hits the fuel filter...
also check the pressure when u rev the motor up.. maybe u just have a weak pump that needs that extra volt or 2 to kick in...


D

[GearHead]

I'll check it before the filter as well.
I had a look in the 1991 fsm i have it said, at idle 34.1 - 39.8 psi.

I always thought mpi needed higher pressures that tpi.

Anyone know it the 8v fuel pump and the 16v fuel pump are interchangeble?

thanks
steve

[Depot]

Im running an 8V gas tank right now with my 16V MFI. I used to run an inline high performance pump and opted to change in the 8 valve tank cuse i had it and the inline was too noisy but i did notice a slight drop in performance. but it does still work well even with the 8 valve tank.. guess I was spoiled with the race pump :D

D

[MLC]

Ok i just checked the fsm it is for a 96 1.6 16 v and it said the pressure should be 30 to 37 psi at a warm idle

[Fullload]

My thoughts would be a pump may put out a higher PSI like we reard once befoe right out of the pump but as you increase the travel and work against gravity to get to the motor after you travel through a filter the pressure can drop drastically.
You will get very little pressure out of the return hose from the regulator as well. The regulator decides what it needs and then sends the rest back to the tank, which is why you don't have much fuel from that hose.
How about this, if you regulator was clogged or not working would it hold fuel longer or not have the desired pressure ( has a higher pressure before it sends it back to the tank) until you get it under a higher RPM which kinda helps the regulator pressure and makes the vehicle run better and then when it goes back to idle the motor cannot burn all the extra fuel therefore a bad idle.
Now i have not seen the truck but is it blowing black smoke out the tailgate or smell like unburnt fuel?
Who knows i could be blowing out my tailpipe with all of this too!!!

Meter all you sensors for a specific value etc... refer to the book and test em all. MASS and MAP and IAC or TPS. I cannot remember if it has AN idle air control but i'm pretty sure that it has a tps instead.

[Fullload]

I'll check it before the filter as well.
I had a look in the 1991 fsm i have it said, at idle 34.1 - 39.8 psi.

I always thought mpi needed higher pressures that tpi.

Anyone know it the 8v fuel pump and the 16v fuel pump are interchangeble?

thanks
steve


I am running the 1.3 8 valve EFI fuel tank and have no problems either.

Zookvet has an early model ford inline pump and has no problems. MAybe she just needs the cobwebs beat out of her.

[GearHead]

I'll drain all the fuel tomorow and fill it with fresh fuel and gas line antifreeze, and then beat on it.

Its just strange, there are no codes and everthing else seem to check out.

One last thought.

Does you 1.6 16v make that rapid sucking sound from the idle air controler, almost like its opening and closing really fast.

My 8v does this but the 16v does not.
I have checked the IAC and it seem to be fine, it is open and sucking air. just no cycling like the 8v does when its cold.

later
steve

[Fullload]

Are you talking about the two little sensors that are on the front of the intake? One hose goes into a steel line that runs down towards the firewall on the top of the intake, and the other dumps into the evap canister?
If so mine clicks/ taps only at certain times and only when the rpms are over 2500.
I was in traffic one day and heard another sidekick doing the same thing so i assumed it was normal.
When depot and i tried to get mine started ( we missed a 12 volt ignition wire) but checked these things to see if he needed them on his truck ( as you know when it comes to depot's motor he lives by the K.I.S.S rule) and my sensors checked out ok.
Mine is a 94 model (similar to yours) and it has the OBD I computer management wheras depot's is a 96 and OBD 2, even though i have never heard the clicking in depots truck it may have something to do with the ECM management, i dunno.
From what i remember reading is these solenoids ( the one that clicks) is the evap system purge valve. when the canister gets full i think it opens and closes ( click click click ) and purges it into the intake until it is clean.

[GearHead]

nope, not those two "sensors", those are vaccum selenods, yes one is for the charcoal canaster the other is for the EGR valve. I was talking about the idle air controle valve, its on the side of the intake closer to the vavle cover, its got a air intake about a 1/2 and two coolant lines and a two wire conector, its metal and about the size of a roll of loonies
On my 8v motor this thing cycles when the truck is first started and then calms down once it warms up. sometimes it will cycle if you go back to idle quickly from higher rpms.

It is quite loud and i would not be suprized if they changed the way it operated in later years.

thanks
steve

[Fullload]

Hm i have never noticed it on mine nor depots. If it is as loud as you describe then could be It. Idle problems and a bad IAC could spell your symptoms. I know on my old 3.1 you could take it out and clean it and put it back in according to the manual, and the car always idled great after that. Worth a shot yo giver a clean i guess. ( sure is cheaper) and hey if it don't work it's still not a waste of time in my mind cause you know it is clean :D

[GearHead]

thanks for the input guys
I play to dig deeper into it on the weekend.
I made a better fuel pressure tester, to test at the fuel rail.
I'll see what the pressure really is.
The other gauge I was suing was a cheap gauge and it my have given me a inaccurate reading.
I'll let you know how things turn out.
later
Steve

[GearHead]

Why do suzuki's always make you bleed.
Just got back from emerg. with four stitches in my thumb.
You know that the sheet metal behind the left tail light i sharp if you wwhak you hand against it.

Well today i fianly had the time to look at the sidekick.
Turns out it was a faulty / weak fuel pump. well could be that poor electrical connection at the sending unit as well.
When i touched it it fell off.
So i swapped tanks.

Also i found the source of the intermetiant electrical problem i have been having.
The plugs under the fueses in the engine bag had there wires rotted off. they were just touching enought to make contact.

Well seems to run fine now.
Thanks foo the help.


later
steve

[Fullload]

Everything mechanical i touch makes me bleed!!! On two of my hands all stitches total 30 from 5 different hospital trips. Not to mention the others that tally in different places on my body!!!

Good to hear you got the problem figured out. Usually fuel pumps seize before they get weak no? anyway it is good to know for future reference!

[Depot]

pumps fail, they dont go weak... corroded wires will simulate weakness.

D

[GearHead]

that's what I figured. I have never had one "wear out" they normally work fine and then they stop.
with all the corrosion I found and cut out the pump was probably not getting full voltage.
The tanks is NFG anyway so I'll scrap it and keep the pump as a spare.

later
Steve

[Depot]

that corrosion at the main fuse box is very very common on kicks.. dunno why but I've seen it a dozen times myself... even bought a junker for 100 bucks that wouldnt start.. fixed those wires and she was mint! :D

D