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1991 Ford Ranger 4.0 V6. Replaced fuel injectors with

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1991 Ford Ranger 4.0...

1991 Ford Ranger 4.0 V6. Replaced fuel injectors with upgraded 24 Lbs injectors. Truck will turn over will not start. Do I need to do anything to re-calibrate these injectors?

Mechanic's Assistant: Has the vehicle turned into a gas hog? And how does it start -- same as usual?

Will not start. Will turn over but not start.

Mechanic's Assistant: Are you fixing your Ranger yourself? What have you tried so far?

Yes. nothing at this point.

Submitted: 20 days ago.Category: Ford
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Answered in 14 minutes by:
5/30/2018
Ford Mechanic: Matt, Engineer replied 20 days ago
Matt
Matt, Engineer
Category: Ford
Satisfied Customers: 23,192
Experience: BEng hons Mech engineering, in auto industry 22 years
Verified

Hello and welcome to Just Answer

If you've replaced the stock injectors with a part that flows more then yes you definitely need to re-calibrate the ECU to accommodate them otherwise the fuel mix will run very rich all the time

why did you uprate the injectors? are you planning to fit a supercharger?

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Customer reply replied 20 days ago
No, simply the most cost effective solution. Here is what I purchased "Bosch-Upgrade-4-Hole-Ranger-Aerostar-Explorer-4-0L-91-95-Fuel-Injector-Set". They are compatible with the 1991 Ranger as well. How do I re-calibrate the ECU?
Ford Mechanic: Matt, Engineer replied 20 days ago

Ok according to my info the stock injector is a 19lb / hr part so by going to 24lb/hr you've increased the fuelling by 21%

so you can either locate a tuning shop that can recalibrate the ECU or purchase the parts to do it yourself

see here

https://www.cjponyparts.com/mustang-computers-programmers/c/60060270/?product_year_mustang=690

however I'd say the best andd cheapest route is to just replace the injectors with the correct flow rate part

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Ford Mechanic: Matt, Engineer replied 17 days ago

Hi
do you still need help?
Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! If you're not pleased, also let me know because rating bad does not result in a refund, there are better options. Rating now will not close this post nor prevent further replies
Thanks Matt

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Customer reply replied 16 days ago
OK I have done more research and pulled out the replacement injectors I installed, to see actual part number. The replacement injector is a Bosch 0-280-150-943 and all of the specs I can find are identical to the original part number 0-280-150-766 except the Ohms. I was mistaken when I thought they were a higher flow rate. The 943 part requires 14.3 Ohms and the original part 766 requires 15.5 Ohms. Does this difference require a ECM reprogramming? The flow rates are the same. If it does not then I still have the same problem--motor turns over strongly, but it will not "catch". Produces excessive white smoke that has a smell of unburnt gasoline. I only have water in the radiator right now so it is not antifreeze being burnt.
Ford Mechanic: Matt, Engineer replied 16 days ago

the slightly lower resistance will alter the fuelling but only by small amount and not enough to stop it starting

lets go back to basics a little

1st check for spark by removing one of the spark plugs and plug it back into its lead and rest it on the metal of the engine ( DO NOT hold it on place by hand) then have your assistant turn the engine over whilst you watch the plug. It should give a fat blue spark at regular intervals.

If not then check that there's power to the coil pack (at the other end of the plug lead) using a meter. If there’s 12V at the pack but no spark then check the ECU power supply (fuse and relay) and also the connections to the crankshaft speed sensor.

If this is OK then check if the car will start using a squirt of quick/ easi start into the intake then this confirms the problem is lack of fuel

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