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Fuel injector positions


madmanperez
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Here comes another stupid question

 

I'll try to keep the synopsis as short as possible. So here goes,

some time ago I had an issue that was tracked down to clogged injectors. Had them replaced and all was good. Years later the same problem arises so this time i change the injectors myself. Car would start surge and then stall. Would not run above 2k. would start high then drop then stall. Let the mechanic look at it, God only knows what he did, but now it ran above 2k but idle would be on the for short of stalling, you'd have to rev it high enough to get it in gear and not stall. In the end I thought since I had a little trouble putting in the new injectors is it possible I wired them wrong? Well I figured what would it hurt if I switch the leads.  I switched the leads and a TPS reset and tada it started running just right.

 

The new injectors are rather loud though.

 

Ok now for the question.

Does it matter what port the injectors are plugged into. It's an '87 Starion ESI-R, so there is a primary and secondary. The primary, 650 and the secondary, 950. Is there a specific position for each? Which one should be closer to the air intake. The injectors are labeled but not the leads.

 

I said earlier that its running right, but with the warmer weather, When the car is fully warmed up the idle drops almost to the floor. Put the car in gear and it drags its tail to get up to where it can make some boost pressure. making a merge or a right on red very tricky.

 

Thanks as always to the gang for all your input.

 

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The larger secondary goes closer to the valve cover.  For the wiring I am not sure, you should be able to look it up in the FSM for wire colors.

Position of the injector probably doesn't matter as much as the correct wires.  I'd swap connectors and see if it runs any better.  If you have the secondary running as the primary it will be overly rich with fuel and be pretty doggy as a result.  

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Are the injectors aftermarket? Rochester/Delphi style? When I had a wideband on my car with those injectors, I could see it idle super lean until the car kicked into closed loop, when the computer could start using the O2 sensor feedback to fix the lean condition.

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Thank you guys,

I appreciate the feed back.

I just love (not) taking off the top hat to verify what injector is where.

Wire colors will be a bit of a pain to check, the injector clips were replaced years ago (and dumba**) didn't mark the new clips.

The injectors are after market, couldn't tell ya what style they are I just found who ever had compatible injectors (south bay fuel injectors). The first replacement was made using injectors from fuel injectors clinic here in Florida, but they don't carry them anymore. I have no idea what a wideband is (though I have seen the term come up quite a bit)

Edited by madmanperez
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29 minutes ago, madmanperez said:

I have no idea what a wideband is (though I have seen the term come up quite a bit)

Wideband air/fuel ratio sensor. Reads the same thing an O2 sensor does (how rich or lean the exhaust gas is pre-catalytic converter), but is much more accurate, and is connected to a separate gauge readout. Pretty much a requirement on these cars when doing any tuning or diagnosing issues such as this.

Edited by GoldStar
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22 minutes ago, madmanperez said:

I looked around, this seems to be a somewhat expensive piece of equipment, $200-$300 and higher. OUCH

But it is worth every penny! Then you know for sure what is going on with your air fuel mixture. 

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Nothing is cheap when doing mods on these cars. The best set up is to use a A/F Gauge, AEM or the like. You have to install a bung in the exhaust pipe at least 36 inches  downstream of the Turbo. And installed at least at a 30 degree angle. AEM gives you all of the information for installing the sensor. Keep your stock 0-2 sensor in place. Or you might want to install a three wire  O-2 Sensor. See how much you have to change when you start to do mods on your fuel delivery. And I haven't even got into fuel  flow with a aftermarket  fuel pump, aftermarket fuel filter and a Rising rate fuel pressure regulator to feed and adjust the larger than stock fuel injectors. Now is where the fun starts !!!!! But, if you need help........We are here.

Bill

Edited by Caliber308
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On 5/17/2022 at 10:22 AM, obsolete said:

Are the injectors aftermarket? Rochester/Delphi style? When I had a wideband on my car with those injectors, I could see it idle super lean until the car kicked into closed loop, when the computer could start using the O2 sensor feedback to fix the lean condition.

Yep, Delphis do run lean until warm up. I have a 950/1150 injector set up with a  3 1/2" MAF -T. It is fun to adjust.

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5 hours ago, madmanperez said:

Thank you guys,

I appreciate the feed back.

I just love (not) taking off the top hat to verify what injector is where.

Wire colors will be a bit of a pain to check, the injector clips were replaced years ago (and dumba**) didn't mark the new clips.

The injectors are after market, couldn't tell ya what style they are I just found who ever had compatible injectors (south bay fuel injectors). The first replacement was made using injectors from fuel injectors clinic here in Florida, but they don't carry them anymore. I have no idea what a wideband is (though I have seen the term come up quite a bit)

FIC Injectors for Starquests are Delphis. They use to use a electric scribe on the side of the injectors to mark the cc size. The Delphis are green and black in color. The South Bay injectors kinda look like Delphis with the spacers but, I would have to see them up close.

 

Edited by Caliber308
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I forgot to mention this. I would check with South Bay to verify that the injectors are Delphis. If so, they will need to see appox. 43.5 psi fuel pressure to operate at their optimum. If you are still running the stock FPR the psi is appox. 34 to 38 psi.

 

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  • 3 weeks later...

OK, I'm assuming that FPR is the Fuel Pressure Regulator (correct) it is stock. Any place in particular place to find a higher pressure regulator? Would that mean I would also have to replace the fuel pump 😣

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Trilogy turbos on eBay (see link below) is the only company I know of that makes an adjustable FPR for these cars.  You wouldn't necessarily have to replace the pump.  It really depends on what you are trying to do.  More info would be helpful.  Are you running a larger turbo and need more fuel?  Increasing boost?  Etc...?

LINK: https://www.ebay.com/itm/234578954580?hash=item369dfec954:g:HjQAAOSwB3Ve-jRs

EDIT:  I should clarify ... Trilogy is the only company I know of that makes a "bolt-on" FPR.  You can drill out the top hat for a standard NPT fitting and then run just about any aftermarket FPR.  Many people on the board here have done this.  Fuel Lab and Aeromotive come to mind.

Edited by techboy
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1 hour ago, techboy said:

Trilogy turbos on eBay (see link below) is the only company I know of that makes an adjustable FPR for these cars.  You wouldn't necessarily have to replace the pump.  It really depends on what you are trying to do.  More info would be helpful.  Are you running a larger turbo and need more fuel?  Increasing boost?  Etc...?

LINK: https://www.ebay.com/itm/234578954580?hash=item369dfec954:g:HjQAAOSwB3Ve-jRs

EDIT:  I should clarify ... Trilogy is the only company I know of that makes a "bolt-on" FPR.  You can drill out the top hat for a standard NPT fitting and then run just about any aftermarket FPR.  Many people on the board here have done this.  Fuel Lab and Aeromotive come to mind.

Spa Turbo USA makes one too, I run one and it works great for me:
|https://spaturbousa.com/products/dodge-conquest-mitsubishi-starion-adjustable-fuel-pressure-regulator-vlrpf512

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  • 2 weeks later...
On 5/19/2022 at 4:53 AM, GoldStar said:

In addition, and should be installed further downstream from the O2 sensor (I think I read somewhere >18 inches away the turbo hotside?). The O2 sensor is still needed for the ECU.

The AEM wideband has an output option that mimics a factory 02 sensor (0-5v if I recall) and so can be used as a direct replacement if desired 

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1 hour ago, gibbon said:

The AEM wideband has an output option that mimics a factory 02 sensor (0-5v if I recall) and so can be used as a direct replacement if desired 

While I can't confirm, I hear that even the narrowband output from modern widebands will cause running issues because our ECUs can't keep up with them.

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10 minutes ago, GoldStar said:

While I can't confirm, I hear that even the narrowband output from modern widebands will cause running issues because our ECUs can't keep up with them.

now that IS interesting because my car has run a bit funny since I put the wideband in... 

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Here is my take...... Use the wideband to only monitor afr ratios. This means that you keep your  stock O-2 hooked up. It might be a good idea to install a three wire O-2 sensor in place of your stock one. P.S. Make sure you mount the wideband O-2 Sensor at least 36 inches downstream from the turbo  and at a 30 degree angle.

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I agree with Bill. I've compared the "simulated narrowband" output from an Innovate wideband to a real narrowband sensor, and the wideband switches at about half the rate. I'd rather run my car on a real narrowband sensor.

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On 6/5/2022 at 9:39 PM, techboy said:

Trilogy turbos on eBay (see link below) is the only company I know of that makes an adjustable FPR for these cars.  You wouldn't necessarily have to replace the pump.  It really depends on what you are trying to do.  More info would be helpful.  Are you running a larger turbo and need more fuel?  Increasing boost?  Etc...?

LINK: https://www.ebay.com/itm/234578954580?hash=item369dfec954:g:HjQAAOSwB3Ve-jRs

EDIT:  I should clarify ... Trilogy is the only company I know of that makes a "bolt-on" FPR.  You can drill out the top hat for a standard NPT fitting and then run just about any aftermarket FPR.  Many people on the board here have done this.  Fuel Lab and Aeromotive come to mind.

No Mods are being made or planned.

Injectors were replaced due to a failure of the previously installed injectors. I don't think the turbo is stock though I believe I'm only making 7 to 10? lbs (still using the original boost gauge) of boost. Plenty for me, no racing, just quick enough to get onto the highway or making red light rights. It's also nice to show off a little that the little lady can still move.

To much rain as of late, making the job difficult to do. I'm not under cover so I have to start the job and finish in one day/afternoon.

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