Questions tagged [fuel-injection]

A method of mixing fuel and air to be consumed by an internal combustion engine.

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29
votes
7answers
9k views

We have fuel injection, why not air injection?

I'm finishing studying EFI systems, which set me thinking about induction more generally. We inject fuel from a high-pressure common rail for many good reasons. We're capable of making stratified ...
16
votes
7answers
43k views

How exactly does running fuel-lean increase the temperature of ignition?

I learned in this question that running an engine fuel-lean will increase the temperature of ignition, among other things such as causing problems with the catalytic converter. I have no idea how or ...
13
votes
2answers
2k views

How to determine injector size for custom engine?

I've got a 2.5 L engine here for which I do not know the performance specs (yet), because it's customized. I need to select injectors for this build, but there seems to be only one equation on the ...
11
votes
2answers
2k views

2001 Infiniti QX4 rough idle - leaking fuel damper vacuum port

I have a bit of an involved problem, so I’ll break it down a bit and try to provide as much detail as possible. My main problem: I have a rough idle on my 2001 Infiniti QX4. It’s not extremely rough,...
10
votes
3answers
1k views

Direct Injection Injectors - How do they prevent blow back into the fuel system?

So I imagine a direct injection injector as a fuel injector squirting fuel directly into the combustion chamber. The amount of pressure in the combustion chamber would seem to be enough to push the ...
9
votes
2answers
4k views

1999 Subaru Forester - bad acceleration, rough shifting

I have a 1999 Subaru Forester with an automatic transmission and a 2.5 Liter Motor. It has poor acceleration and rough shifting I started to notice 'hesitation' on take off. It just slowly appeared....
9
votes
3answers
12k views

How much fuel does it take to start an engine?

I appreciate this is a question that can't be answered in facts and figures, so I'm after a general idea. I drive a 1986 Supra, which has a modest 2.8-litre engine. I often shut the engine off while ...
8
votes
3answers
34k views

Best way to repair a rotten fuel line?

I believe the feed line in my fuel system has rotted. If I'm going to cut out the rusted areas and splice a new line in... Is it best to flare a hardline? Is steel the OEM material? How would I ...
8
votes
2answers
4k views

Why is the effect of a bad fuel pump more noticable at higher speeds?

I get that the main effect of a bad fuel pump is that the engine will cut out at higher speeds, and that this is often not easily noticeable until that happens because there are little or no prior ...
8
votes
1answer
406 views

Changing from two heated O2 sensors to a single O2 sensor

I'm going to be removing a Motorcraft 2150 carburetor in a 2.8L V6 and swapping it for a Ford CFI (and ECU) from a 3.8L V6. I've just recently pulled everything (ECU, throttle body, sensors, harnesses,...
7
votes
9answers
110k views

Strong vibrations when idling even after replacing engine mounts (automatic transmission)

I have a '93 Acura Integra with automatic transmission. Ever since I got it some time ago the car has been vibrating a lot when stopped at a light, for example. The vibration is worse when in gear ...
7
votes
4answers
14k views

Advantages of direct vs sequential fuel injection

I understand that direct injection puts the air/fuel mix into the cylinder body directly vs the intake valve like the sequential does. What are the advantages of doing so? E.g. does it yield a ...
7
votes
1answer
14k views

What are some Seafoam Alternatives

I read this procedure for using Sea Foam ( also listed on their website ) to clean the intake manifold, injectors and crankcase. I think this would be useful for my vehicle, however Sea Foam isn't ...
7
votes
2answers
84k views

I have an issue with Stepping on gas and no increase in speed

It only happens rarely.. but sometimes when stepping down the gas it would suddenly max out the speed gauge, and you hear the very loud engine noise as if i stepped down the gas all the way, but what ...
7
votes
1answer
2k views

How are fuel injectors controlled?

I took the fuel injectors off of a wrecked Volvo 850 GLT 1996. I was testing them to see if they still worked by simply supplying voltage to them, and they do. I noticed that when I increase or ...
7
votes
1answer
3k views

Warm fuel injected engine stutters when accelerating

I have a 1994 Honda Concerto 1.5l gasoline car, fuel injected. When the engine is cold there are no accleration problems. But once it warms up it stutters if I step hard on the gas. When it does ...
7
votes
1answer
135 views

Is an injector an injector?

In general terms at least - lately the engines I've been working on are diesels and I've never had to troubleshoot fuel injection problems on gasoline/petrol engines. So, I'm wondering, how many ...
7
votes
3answers
5k views

Fiat Punto Wont Start. Fuel Light & Three warning lights flashing

My Fiat Punto 1.2 Year 2000 MK2 (I believe) will not start. The engine turns over but the car won't start. The fuel light is flashing and petrol gauge says empty which isn't the case. There are three ...
6
votes
4answers
2k views

How to tune the ECU / fuel trim in a custom-built engine

I have a Gen VI 454 in my Suburban that needs some work. I'm thinking about turning it into a 496 stroker. Once I find a list of mechanical components (crank, cam, pistons, heads... everything) that I'...
6
votes
2answers
180 views

How can vehicles run on E?

Sorry if this topic is too open ended I'm new to this site. I am studying engines and how they work and I keep wondering, how do cars with no gas still manage to run for a few extra miles? If you ...
6
votes
1answer
10k views

Difference between fuel pressure and fuel rail pressure

In OBD PID wiki page, there are 2 PIDs listed: Fuel pressure and Fuel rail pressure. Are both of them the same? Can someone please give an elaborate explanation of it - What exactly are they ...
6
votes
2answers
1k views

Calculate amount of fuel injected

How do I calculate the amount of fuel injected (both gasoline and diesel cars). I want an instantaneous value. http://www.rceng.com/technical.aspx Websites like these ask for 'Desired Crankshaft Power'...
6
votes
1answer
72 views

Fuel system question

See red arrow in the image. I place fuel additive in my car, all of the additives went into that pipe (in the red arrow image) because i didnt know how to place it. Will it still work? or just a waste?...
6
votes
1answer
786 views

1998 V6 Mustang -20+ LTFT on both banks

I just finished doing a bunch of work on my Mustang (replaced all gaskets down to head gaskets on engine, had the heads milled and a valve job done, replaced all the fuel injectors, new fuel injector, ...
6
votes
2answers
4k views

What would cause differences in spark plug wear on a '97FordRanger?

The mileage on these plugs is unknown, as this is a used vehicle w/o a complete service record. All 3 plugs on the driver side (4,5,6) were almost completely eroded. The 3 on the passenger side (1,2,...
6
votes
3answers
10k views

Motorcycle with EFI not starting well

I have a 2012 Kawasaki W800. On cold mornings it is difficult to start - it turns over quite a few times before it catches. This is compared to my old carburettor bike which started instantly with the ...
6
votes
1answer
12k views

Re-programming injection pump on French Ford Focus TDCi

I replaced the engine on my 2003 Ford Focus (French TDCi) and I plugged it to clear the error codes. Now it starts ok but stops after 10 minutes. I read that when a new injection pump is installed, ...
6
votes
1answer
465 views

2007 Chevy HHR, check Engline light ON, 2 to 4 cranks to start, won't accelerate beyond 80 mph

I took the car to my local mechanic two weeks ago with the problems described above. He replaced the air filter, spark plugs, and did an oil change, saying those were likely the issue. After these ...
6
votes
2answers
196 views

Is my 1999 blazer having transmission problems?

I have a '99 Chevy Blazer. It never wants to get moving right away. It takes 30 seconds to a minute before I can get fully going. It also shakes when I am at a red light or stopped. I noticed today ...
5
votes
5answers
1k views

What actually affects engine compression ratios?

I always assumed that the less "square" (or more "undersquare") a motorcycle engine was, the higher the compression ratios it can have. But a survey of several bikes -- from cruisers to supersports, ...
5
votes
4answers
387 views

Why isn't injection managed to use the entire intake stroke?

As far as i know, electronic fuel injectors only know two discrete states, on or off. Under light load (ie. low rpm and throttle) the injector doesn't have to deliver much fuel. So naturally the ...
5
votes
3answers
2k views

Toyota Yaris Fuel Saving

I use Toyota Yaris, 2005 Model, 1.3L, automatic shift, gasoline-powered vehicle, at 141.000KM. I go to work totally 30KM by my car on the highway weekdays. On the road my maximum speed is 90KM/H and ...
5
votes
2answers
1k views

What is the difference between “multi port” and “combined port” fuel injection?

I have heard these terms tossed around quite a bit and I understand that fuel injection is needed in order to inject fuel in to the engine (from a fuel rail/injectors?). What is the difference ...
5
votes
3answers
5k views

Why is a volume test necessary when diagnosing fuel delivery problems?

I suspect my fuel pump causing intermittent driveability issues. I checked the fuel pressure at the fuel rail and it seems like the pressure is fine: ~2.4 bar at idle, 3.1 bar at engine off (3.09 bar ...
5
votes
3answers
7k views

Why do some engines use both TPS and MAP sensors?

I ask because I've always thought it peculiar that the OEM LS1 throttle body has provision for both MAP sensor and TPS. Since intake manifold pressure depends on how open the throttle plate is, I ...
5
votes
4answers
58k views

Gas pedal not responding

It just doesn't work, as if I weren't even pressing it and it happens regardless of the speed. I have to turn the engine off and on again and it'll work for another 3 or even up to 20 minutes ...
5
votes
3answers
6k views

Car runs uneven and jerky, but why? (Mazda 626)

I have a Mazda 626 (sedan) -97 and lately its been running uneven and jerky. Have had in in for repairs and changed battery, oil+filter and spark plugs. Still had problems and tried to use a engine ...
5
votes
1answer
14k views

Motorcycle: Fuel Injection light comes on after 5 mins of riding

I've bought a brand new bike and have had it for about 2 months. Later this week I noticed that after about 5 mins of riding the Fuel Injection light comes back on. I stop the bike, turn the ignition ...
5
votes
0answers
610 views

1995 VM Jetta/Vento - ECU pinout for my car

I own a 95 Vento GL (Jetta for the american market), with an 1.8 8v, 90hp ADD model engine. The ECU for this model is marked with part number 037 906 021A. I have checked with VAG-COM software and it ...
4
votes
3answers
2k views

Is it OK to run a diesel engine with a blocked fuel injector return line?

Recently, a squirrel paid a visit to the engine compartment of my 1999 VW (it's a diesel 1.9 TDI). Besides leaving some crabapples as gifts, it chewed clean through one of the fuel injector return ...
4
votes
2answers
116 views

Slightly low MPG - need help with my checklist

I own a '91 Ford Sierra 2.0 8V SOHC. Fairly simple engine, utilizes a Bosch L-jetronic fuel injection system. (EFI has following components: MAF, MAP, TPS, IAC, narrow-band o2 sensor, TFI module for ...
4
votes
3answers
3k views

Percent of Air and Fuel used for Combustion

I've had this question for a long time. I know the percent will differ based upon the throttle position and will be either by stoichiometric ratio or rich mixture. The stoichiometric ratio (AFR) ...
4
votes
2answers
12k views

Is the after catalyst oxygen sensor used for engine mixture control?

People have often stated that the oxygen sensor installed behind the catalytic converter in a common gasoline engine setup has only one function: to test the health of the catalytic converter. ...
4
votes
2answers
942 views

Sticking Injector or dead CIS?

I have an VW 83 gti (mostly stock except for MSD system) that is having some troubles starting. Basically, when the engine is cold, it starts like a dream. I was previously having some very rough idle ...
4
votes
2answers
2k views

Is a secondary air injection pump motor necessary?

My check engine light came on and the mechanic said the problem is that the secondary air injection pump motor broke. It's a used car (2004 VW new beetle) with about 150,000 miles on it and the parts ...
4
votes
1answer
2k views

Starting fluid, does it require a spark or autoignite?

If a four stroke gasoline engine (inline-four, digital fuel injection) starts with starting fluid (but not without it, and stops firing when the spray is removed), is this an indication that the spark ...
4
votes
1answer
9k views

Repair or replace frayed fuel injection wiring harness?

This is on a 2008 Chevy Impala, 3.5L V6, non-flexfuel. Recently got cylinder 1 misfire / ignition failure codes. An investigation revealed that mice had gotten into my garage, made themselves at ...
4
votes
1answer
6k views

Engine suddenly died on uphill, then went back to life after a few tries

Car: BMW 318 TDS Compact. 90HP. 168.000KM Situation: was driving a very intense uphill section at 70km/h, in 4th gear (2.000 rpm). Everything was ok. Engine sound, temperature, etc... Suddenly, ...
4
votes
0answers
944 views

LTFT way too high, O2 seems sane

Issue Car in question is a Renault Clio B 1.2 16V with about 85KKm. I experience two issues: Intermittent starting problems, independent of hot or cold engine. When the problem occurs I need to ...
4
votes
0answers
63 views

Why did my van hesitate, then stall and not restart?

I have a 1989 Econoline 250 with low miles (60k) was driving on the highway today when I suddenly lost power, tried to give it gas but it hesitated, then stalled so I pulled off. Check engine light ...